2nd Vietnamese Secondary Mathematics Contest






A2. The points X, Y and Z are chosen on the side BC, CA, AB of a given triangle ABC, respectively such that BX = CY = AZ. Prove that the triangle XYZ is equilateral if and only if so is the triangle ABC.

A3. Give a collection of real numbers A = (a1, a2,...an ), denote by A(2) the 2-sums set of A, which is the set of all sum a1+ai, for 1 ≤ i < j ≤ n. Give that A(2) = (2,2,3,3,4,4,4,4,4,5,5,5,6,6), determine the sum of squares of all elements of the original set A.

A4. Let M be a point on a given line segment AB. Draw three semicircles whose diameters are AM, BM, AB respectively, such that they are on the same side with respect to AB. Let I be the incenter and r be the inradius of the curvilinear triagle ABM (whose sides are the three semicircles just contructed). Prove that when M moves on the line segment AB, the locus of I is an are of an ellipse whose spanning chord passes through one of its foci.





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1st Vietnamese Secondary Mathematics Contest



(For 6th grade)

A2. Let n be a positive integer and let U(n) = {d1; d2;...dm} be the set of all positive divisors of n. Prove that
d12 + d22 + ...+ dm2 <
(For 7th grade)

A3. Prove that


 where a, b, c are there positive numbers satisfying abc = 1.

 A4. Solve the equation 
  
A5.  Let ABCD be a square, M is a point lying on CD (MC, MD). Through the point C draw
a line perpendicular to AM at H, BH meets AC at K. Prove that:

1) MK is always parallel to a fixed line when M moves on the side CD.

2) The circumcenter of the quadrilateral ADMK lies on a fixed line.

A6. Let a, b, c be positive real numbers such that abc = 1. Prove that

(For upper secondary schools)

A7. Conside all triangles ABC where A < B < C≤
Find the least value of the expression: M = cot2A + cot2B + cot2C + 2(cotA - cotB)(cotB - cotC)(cotC - cotA).

A8. Suppose that the tetrahedron ABCD statisfies the following conditions:  All faces are acute triangles and BC is perpendicular to AD.  Let ha, hd be respectively the lengths of the altitudes from A, D onto the opposite faces, and let 2α  be the measure of the dihedral angle at edge BC, d is the distance between BC and AD. Prove the inequalityl: 
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How to Draw a Crossword Puzzle?



Get a thrill from drawing a crossword puzzle---or go crazy trying to do it.

Addiction comes in many forms: alcohol, drugs, crossword puzzles. You know you are addicted when the first thing you do every morning is pull out your paper and begin working on the crossword puzzle. However, unlike alcohol and drugs, word puzzles are healthy addictions that strengthen your mind. According to Discovery Health, crossword puzzles "stimulate the brain and increase the connections between brain cells." But when you discover solving crossword puzzles is no longer a tease, it is time to move on to something more challenging: drawing a crossword puzzle.

Instructions
1. Make a list of words and clues you would like to include in the puzzle. The words should vary in length, but avoid two-letter words. For example, a hint can be "Tree," and the answer "Maple." Or if the clue is "Hoosier State," the answer is "Indiana." List at least 20 words and clues.

2. Use your ruler and pen to draw a 15-by-15-box grid. Make 16 vertical lines 1/2 inch apart. Add 16 horizontal lines 1/2 inch apart to make squares out of the vertical lines. You should have 15 rows of squares across and 15 columns of squares down.

3. Write the words on the grid so two or more words connect. Label the first box of each word with a number.

4. Use diagonal symmetry, which means to match black squares diagonally. According to the Crossdown website, "If a black square appears in the upper left-hand corner, there must be one in the bottom right-hand corner." This is true for the entire puzzle. You should not have more than one-sixth of the puzzle filled with shaded squares.

5. Fill in the remaining white space with words, abbreviations and phrases. Separate the clues into two lists, across and down. Begin numbering the boxes from lowest to highest and jotting down the clues.

6. Separate the clues into two lists, across and down. Begin numbering the boxes from lowest to highest and jotting down the clues.

7. Erase the answers from the crossword puzzle to finish, or repeat Step Two and shade the areas on the new grid to correspond to the old. Add the numbers to the corresponding positions and write the clues at the bottom to finish.

Tips & Warnings

Save time by inputting words and clues in an online helper that will automatically create your crossword.

References
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How Do I Beat the Math Puzzle in Tombscape?



How Do I Beat the Math Puzzle in Tombscape?

 You will not need a calculator to beat the math puzzle in "Tombscape."

In "Tombscape," a point-and-click flash adventure game, you travel through a treacherous tomb and collect treasure while fending off deadly spiders and avoiding traps. "Tombscape" includes several puzzles that must be solved before you can progress to the next adventure. About a quarter of the way through the game, you'll enter a room that has two puzzles. The puzzle on the left side of the room requires you to solve five simple math equations and enter your answers by clicking on arrows to cycle through the digits on the corresponding dials.

Instructions

  1. 1
    Multiply 6 by 3 to get 18, then subtract 9 to total 9. Press the up arrow at the first dial until you reach "9."
  2. 2
    Multiply 3 by 5 to get 15, then subtract 6 to total 9. Click the arrow at the second dial until you reach "9."
  3. 3
    Multiply 2 by 8 to total 16, then subtract 9 to equal 7. Enter "7" at the third dial.
  4. 4
    Subtract 3 from 7 to get 4, then subtract 4 to total zero. The fourth dial is already set at "0," so there is no need to change anything.
  5. 5
    Add 4 and 4 to total 8, then divide by 8 to total 1. Click on the arrow once to reach "1" at the final dial.

Tips & Warnings

  • You cannot return to any room you've already visited once you progress past it, so collect all the coins and gems in a room before you move forward.

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Play Free Sudoku Online



Try to beat the clock with these free Sudoku puzzles of varying difficulty, from easy to extra-challenging. Play these Sudoku online or print and solve on paper.

Free Sudoku Puzzles to Print

Addicted to Sudoku puzzles? About Puzzles has hundreds of free Sudoku Puzzles for every range of expertise. These Sudoku puzzles range in difficulty from extra easy to extra challenging. No need to be a math whiz, Sudoku puzzles are solved using logic and reasoning.

Play Sudoku Online

If you're like the majority of Sudoku puzzlers, then you probably prefer solving Sudoku puzzles online. Here, you'll find free sudoku games of varying levels of difficulty, from kids' Sudoku with 4x4 or 6x6 square grids to Monster Sudoku, with its brain-crunching 12x12 grid.

Sudoku - Addictive Japanese Number Puzzles

Discover Sudoku, a popular number puzzle that is solved with logic and reasoning.

SuDoku Puzzles for Beginners

Extra-Easy SuDoku puzzles for beginners courtesy of Dave Fisher, your guide to Puzzles at About. These puzzles are print-friendly with four SuDoku puzzles to a page and are intended for those who are new to SuDoku and are just developing their Sudoku solving strategies.

Easy SuDoku Puzzles

Easy SuDoku puzzles courtesy of Dave Fisher, your guide to Puzzles at About. These puzzles are print-friendly with four SuDoku puzzles to a page and are intended for those who are new to SuDoku and are just developing their Sudoku solving strategies.

Intermediate SuDoku Puzzles

Free SuDoku puzzles of medium difficulty courtesy of Dave Fisher, your guide to Puzzles at About. These puzzles are print-friendly with four SuDoku puzzles to a page and are intended for those who are new to SuDoku and are just developing their Sudoku solving strategies.

Challenging SuDoku Puzzles

Free challenging SuDoku puzzles courtesy of Dave Fisher, your guide to Puzzles at About. These puzzles are print-friendly with four SuDoku puzzles to a page and are intended for experienced SuDoku solvers.

Extra-Challenging SuDoku Puzzles

Free extra-challenging SuDoku puzzles courtesy of Dave Fisher, your guide to Puzzles at About. These puzzles are print-friendly with four SuDoku puzzles to a page and are intended for expert SuDoku solvers.

Free Sudoku Puzzle Game

Free online Sudoku puzzles for you to enjoy. Thousands of Sudoku puzzles in four difficulty levels: Simple, Easy, Intermediate and Expert.

Free Alphadoku Puzzles

For the Alphadoku Puzzle enthusiast, printable Alphadoku Puzzles for every level of expertise.

Futoshiki Puzzles

Futoshiki is a type of Japanese number puzzle which, like Sudoku, requires logic rather than mathematical computations to solve. Like Sudoku, arrange the numbers so that they appear only once in each row or column, while taking into consideration the greater and less than symbols that appear in the puzzle. Solve these puzzles online or print for solving on paper.

How to Play Sudoku Online

Tips and tricks on how to play Sudoku Online on your computer.

How To Solve SuDoku

This tutorial will help the novice Sudoku puzzler learn some basic Sudoku solving strategies, as well as tips and tricks on how to solve these popular number puzzles with reasoning and logic.

Kids' Sudoku - Sudoku Puzzle Books for Children

Now kids can enjoy these addictive Japanese number puzzles just like the grown-ups do! Excellent for trips or long waits, these books will help young solvers aged 8 and over improve their logic and math skills and assist them in developing patience and concentration.

Sudoku Puzzle Books

Addicted to Sudoku? Here's a selection of books to help ease your craving for these popular number puzzles.

SuDoku Games - Board Games and Electronic Games

If you're looking to buy sudoku games, you've come to the right place. Shop online and get the best price for electronic, hand-held sudoku games, wooden sudoku board games, wipe-off sudoku board games, sudoku card games and sudoku games for kids.

BrainBashers Sudoku

Six difficulty levels from Very Easy to Super Hard. Solve online or print and solve.

Daily Sudoku

Four versions of the popular number game: Classic, Monster, Kids and Squiggly (grid isn't divided into 9 squares, but into irregular blocks). Enjoy playing these puzzles online. Printable puzzles are also available for those who prefer to solve Sudoku on paper (requires Adobe Acrobat Reader).

Jigsaw Sudoku

This online sudoku game, as its name would imply, is a cross between the jigsaw puzzle and the sudoku puzzle. Move the number squares to their proper place. Easy 6x6 grid.

New York Times Sudoku

These puzzles, updated daily, come in Easy, Medium and Difficult versions, so you can select the one which best suits your level of expertise. Play these sudoku online or print and solve (requires Adobe Acrobat Reader). Unlike the Daily Crossword, it's free!

Opensky Sudoku Generator

This service lets you create up to 50 sudoku puzzles in Adobe PDF format to print and solve. You can choose from easy, medium, hard, or very hard puzzles or have the program randomly select puzzles for you to solve.

Please Give us Your Feedback - SuDoku Poll #2

About Puzzles SuDoku Poll #2 - How often do you do SuDoku Puzzles?

Please Give us Your Feedback - SuDoku Poll #3

About Puzzles SuDoku Poll #3 - Where do you do SuDoku puzzles?

Shockwave - Daily Sudoku

Play these easy, medium and hard sudoku online. The game lets you know immediately if you've made a mistake and won't let you enter the wrong number.

Sudoku - Wikipedia

Everything you ever wanted to know about Sudoku from the folks at Wikipedia.

Sudoku History

Find out the origins of this popular number puzzle game.

Sudoku of the Day

Compete with other players to see who can solve these diabolical sudoku puzzles the fastest.

Sudoku Online

Here's an online version of the popular puzzle game that has taken the world by storm.

SuDoku Solver

A freeware program designed to help in solving sudoku. It uses the same logical methods to solve puzzles as a human would, and explains how it arrived at that conclusion. Excellent aid for those new to Sudoku who need a bit of help figuring out how to play.

Sudoku Terms and Jargon

A comprehensive list of sudoku terms with definitions.

Super Sudoku

Online Sudoku generator and solver. Generates and/or solves regular sudoku puzzles or the extra challenging Super Sudoku (a 16x16 grid which uses the letters A-F as well as the numbers 1-9). You must register to play, it's free.

Surviving Sudoku or...

How the Japanese puzzle's invasion has rocked the world of American crossword writers -- and what they’re doing to cope. Interesting article by Matt Gaffney.

USA Today Sudoku

Available in online, print and mobile phone versions.

Web Sudoku

Features easy, medium, hard and evil sudoku that you can play online, but you need to buy the Deluxe version for the solutions. You can also create your own customized sudoku ebook with 8 pages of either easy, advanced, kid or combination puzzles.

Who is Leonhard Euler? - Did he invent Sudoku?

Who is Leonhard Euler and did he invent the Sudoku puzzle more than 220 years ago?

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Math Puzzles and Games



Free online math games for math lovers: mathematical puzzles, prime numbers, cross sums, memes, Sudoku, Kakoru, logic puzzles, brainteasers and more. Good for students trying to improve their math skills.

Math Games from About Mathematics

Interactive math games, math brain teasers and math puzzles from your Mathematics Guide at About.

The Strange Case of 142,857

142,857 is just a number but it has some intriguing aspects and, when multiplied and manipulated, it displays some amazing properties.

K-12 Math Puzzles

From the Math Forum, a collection of math puzzles and math line puzzles for students. Try the 'Year Game' which is especially challenging for the year 2000.

Kakuro Puzzles - Books for Kakuro Puzzlers

More and more people are turning to puzzles and brainteasers as a way to keep their minds sharp as they age. In Kakuro, the objective of the puzzle is to fill in the numbers so that every row and column adds up to the corresponding numerical indicator. These books feature Kakuro, Meiro, Tensen, Hanjie, Sum Squares, Wordoku and other fun puzzle games.

Kakuro Puzzles Index

Fill in the puzzle so that every row and column adds up to its corresponding numerical indicator. No number may repeat in any row or column. These are print-friendly versions.

Magic Squares

A magic square is an arrangement of numbers in a square, with each number occurring once, and the sum of the entries of any row, column, or diagonal is the same. Historical background and classroom activities included.

Math & Logic Puzzles

From The William Levering School (Philadelphia, PA), math, geometry and logic puzzles that teach kids critical thinking.

Math Puzzle Books

A selection of books featuring math puzzles and games using various math concepts : polygons, numbers, topology, division, mazes, logic, magic squares, chess, cards, origami and much more!

Math Puzzlers!

A good selection of math puzzles. If you're stumped go here for the solutions.

Mathematics Miscellany and Puzzles

Advanced math logic puzzles as well as math puzzles and riddles. Many interactive (Java).

Mathmania

Illustrated encyclopedic portal covering a wide range of topics including puzzles. Very interesting. Don't miss the optical illusions.

Mazes to Mathematics

There's more to mazes than minotaurs and meandering.

Perplexus

Check out "flooble's perplexing puzzle portal", featuring logic, probability, number, and paradox problems. You can post solutions or pose your own brainteasers (simple registration required to post comments). Worth a visit.

Play With Your Mind Math Puzzles

Practice your math and number skills with these free online math games from Play With Your Mind. These games entail equations, mathematical relationships, mental math and more.

Prime Puzzles

If you like math problems involving prime numbers and algorithms then this site should add up to a good time for you.

Rising Star Puzzle Mathematical Puzzle

The challenge is to enter a different number in each circle (from 1 through 21) so that the sum of the digits in any straight line is the same.

Sudoku Puzzles - Easy - Intermediate - Expert

Puzzles range in difficulty from extra easy to extra challenging. No need to be a math whiz, these puzzles are solved using logic and reasoning.

Word Math

Word Math test the solver's analytical abilities with a blend of mathematical, logic, and language puzzles. Interactive.
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Teaching Math to the Talented



Which countries—and states—are producing high-achieving students?
By Eric Hanushek, Paul E. Peterson and Ludger Woessmann

In Vancouver last winter, the United States proved its competitive spirit by winning more medals—gold, silver, and bronze—at the Winter Olympic Games than any other country, although the German member of our research team insists on pointing out that Canada and Germany both won more gold medals than the United States. But if there is some dispute about which Olympic medals to count, there is no question about American math performance: the United States does not deserve even a paper medal.
Maintaining our productivity as a nation depends importantly on developing a highly qualified cadre of scientists, engineers, entrepreneurs, and other professionals. To realize that objective requires a system of schooling that produces students with advanced math and science skills. To see how well schools in the United States do at producing high-achieving math students, we compared the percentage of U.S. students in the high-school graduating Class of 2009 with advanced skills in mathematics to percentages of similarly high achievers in other countries.
Unfortunately, we found that the percentage of students in the U.S. Class of 2009 who were highly accomplished in math is well below that of most countries with which the United States generally compares itself. No fewer than 30 of the 56 other countries that participated in the Program for International Student Assessment (PISA) math test, including most of the world’s industrialized nations, had a larger percentage of students who scored at the international equivalent of the advanced level on our own National Assessment of Educational Progress (NAEP) tests. Moreover, while the percentage of students scoring at the advanced level on NAEP varies considerably among the 50 states, not even the best state does well in international comparison. A 2005 report from the National Academy of Sciences, Rising Above the Gathering Storm, succinctly put the issue into perspective: “Although many people assume that the United States will always be a world leader in science and technology, this may not continue to be the case inasmuch as great minds and ideas exist throughout the world.”
The Demand for High Achievers
The gap between the burgeoning business demand for a highly accomplished workforce and a lagging education system has steadily widened. Even as the United States was struggling with a near 10 percent unemployment rate in the summer of 2010, businesses complained that they could not find workers with needed skills. New York Times writer Motoko Rich explained, “The problem…is a mismatch between the kind of skilled workers needed and the ranks of the unemployed.”
Skill shortages have severe consequences for a nation’s overall productivity. Two of the authors of this report have shown elsewhere that countries with students who perform at higher levels in math and science show larger rates of increase in economic productivity than do otherwise similar countries with lower-performing students (see “Education and Economic Growth,” research, Spring 2008).
Public discourse has tended to focus on the need to address low achievement, particularly among disadvantaged students. Both federal funding and the accountability elements of No Child Left Behind (NCLB) have stressed the importance of bringing every student up to a minimum level of proficiency. As great as this need may be, there is no less need to lift more students, no matter their socioeconomic background, to high levels of educational accomplishment. In 2006, the Science, Technology, Engineering, and Mathematics (STEM) Education Coalition was formed to “raise awareness in Congress, the Administration, and other organizations about the critical role that STEM education plays in enabling the U.S. to remain the economic and technological leader of the global marketplace for the 21st Century.” In the words of a National Academy of Sciences report that jump-started the coalition’s formation, the nation needs to “increase” its “talent pool by improving K–12 science and mathematics education.”
A Focus on Math
We give special attention to math performance because math appears to be the subject in which accomplishment in secondary school is particularly significant for both an individual’s and a country’s economic well-being. Existing research, though not conclusive, indicates that math skills better predict future earnings and other economic outcomes than other skills learned in high school. The American Diploma Project estimates that “in 62 percent of American jobs over the next 10 years, entry-level workers will need to be proficient in algebra, geometry, data interpretation, probability and statistics.”
There is also a technical reason for focusing our analysis on math. This subject is particularly well suited to rigorous comparisons across countries and cultures. There is a fairly clear international consensus on the math concepts and techniques that need to be mastered and on the order in which those concepts should be introduced into the curriculum. The knowledge to be learned remains the same regardless of the dominant language spoken in a culture.
Data and Methodology
Our analysis relies on test-score information from NAEP and PISA. NAEP, the National Assessment of Educational Progress, is often called the nation’s report card. It is a large, nationally representative assessment of student performance in public and private schools in mathematics, reading, and science that has been administered periodically since the early 1970s to U.S. students in 4th grade and 8th grade, and at the age of 17. PISA, the Program for International Student Assessment, is an internationally standardized assessment of student performance in mathematics, science, and reading established by the Organisation for Economic Co-operation and Development (OECD). It was administered in 2000, 2003, and 2006 to representative samples of 15-year-olds in all 30 OECD countries (which include the most developed countries of the world) as well as in many others.
We focus on performance of the international equivalent of the U.S. high-school graduating Class of 2009 at the time when this population was in the equivalent of U.S. grades 8 and 9. NAEP was administered to U.S. 8th graders in 2005, while PISA 2006 was given one year later to students at the age of 15, the year at which most American students are in 9th grade.
In 2005, NAEP tested representative samples of 8th-grade public and private school students in each of the 50 states in math, science, and reading. For each state, NAEP 2005 calculates the percentage of students who meet a set of achievement standards: a “basic” level, a “proficient” level, and an “advanced” level of achievement. The focus of this report is the top performers, the percentage of students NAEP found at the advanced level of achievement (subsequently referred to as “advanced”).
Only 6.04 percent of the students in the United States in 8th grade in 2005 scored at the advanced level in math on the NAEP. Some critics feel that the standard set by the NAEP governing board is excessively stringent. However, the 2007 Trends in International Math and Science Study (TIMSS 2007), another international test that has been administered to students throughout the world, appears to have set a standard very similar to NAEP 2005, as only 6 percent of U.S. 8th graders scored at the advanced level on that test as well.
We use the NAEP 2005 advanced standard to compare U.S. performance with that in other countries. Because U.S. students took both NAEP 2005 and PISA 2006, it is possible to find the score on PISA that is tantamount to scoring at the advanced level on NAEP, i.e., the score that will yield the same percentage of students as the percentage of U. S. students who scored at the advanced level on the NAEP.
A score on PISA 2006 of 617.1 points is equivalent to the lowest score attained by anyone in the top 6.04 percent of U.S. students in the Class of 2009. (The PISA assessment has an average score of 500 among OECD students and a standard deviation of 100.) It is assumed that both NAEP and PISA tests randomly select questions from a common universe of mathematics knowledge. Given that assumption, it may be further assumed that students who scored similarly on the two exams will have similar math knowledge, i.e., students who scored 617.1 points or better on the PISA test would have been identified at the advanced level had they taken the NAEP math test. Inasmuch as a score of 617.1 points is more than one standard deviation above the average student score on the PISA, it is clear that a group of highly accomplished students has been isolated. (For more methodological details, see sidebar.)
Because representative samples of student performance on NAEP 2005 are available for each state, it is possible to compare the percentages of students in the Class of 2009 who were at the advanced level for each state to the percentage of equally skilled students in countries from around the globe.
In short, linking the scores of the Class of 2009 on NAEP 2005 and PISA 2006 provides us with the opportunity to assess from an international vantage point how well the country as well as individual states in the United States are doing at lifting students to high levels of accomplishment.
U. S. Math Performance in World Perspective
We begin with an overall assessment of the relative percentages of young adults in the United States and other countries who have reached a very high level of mathematics achievement. It is frequently noted that the United States has a very heterogeneous population, with large numbers of immigrants. Such a diverse population, with students coming to school with varying preparation, may handicap U.S. performance relative to that of other countries. For this reason, we also examine two U.S. subgroups conventionally thought to have better preparation for school—white students and students from families where at least one parent is reported to have received a college degree—and compare the percentages of high-achieving students among them to the (total) populations abroad.
Overall results. The percentage of students in the U.S. Class of 2009 who were highly accomplished is well below that of most countries with which the United States generally compares itself. While just 6 percent of U.S. students earned at least 617.1 points on the PISA 2006 exam, 28 percent of Taiwanese students did. (See Figure 1 for these results as well as for the international rank of each U.S. state.)

Click to enlarge
It is not only Taiwan that did much, much better than the United States. At least 20 percent of students in Hong Kong, Korea, and Finland were similarly highly accomplished. Twelve other countries had more than twice the percentage of advanced students as the United States: in order of math excellence, they are Switzerland, Belgium, the Netherlands, Liechtenstein, New Zealand, the Czech Republic, Japan, Canada, Macao-China, Australia, Germany, and Austria.
The remaining countries that educate a greater proportion of their students to a high level are Slovenia, Denmark, Iceland, France, Estonia, Sweden, the United Kingdom, the Slovak Republic, Luxembourg, Hungary, Poland, Norway, Ireland and Lithuania.
The 30-country list includes virtually all the advanced industrialized nations of the world. The only OECD countries producing a smaller percentage of advanced math students than the United States are Portugal, Greece, Turkey, and Mexico. The performance levels of students in Spain and Italy are statistically indistinguishable from those of students in the United States, as are those of students in Latvia, which has subsequently joined the OECD.
State-level performance. The percentage of students scoring at the advanced level varies among the 50 states. Massachusetts, with over 11 percent of its students at the advanced level, does better than any other state, but its performance trails that of 14 countries. Its students’ achievement level is similar to that of Germany and France. Minnesota, with more than 10 percent of its students at the advanced level, ranks second among the 50 states, but it trails 16 countries and performs at the level attained by Slovenia and Denmark. New York and Texas each have a percentage of students scoring at the advanced level that is roughly comparable to the United States as a whole, Lithuania, and the Russian Federation.
Just 4.5 percent of the students in the Silicon Valley state of California are performing at a high level, a percentage roughly comparable to that of Portugal. The lowest-ranking states—West Virginia, New Mexico, and Mississippi—have a smaller percentage of the highest-performing students than Serbia or Uruguay, although they do edge out Romania, Brazil, and Kyrgyzstan.
In short, the percentages of high-achieving students in the United States—and in most of its individual states—are shockingly below those of many of the world’s leading industrialized nations. Results for many states are at a level equal to those of third-world countries. (Click the image below for an interactive map providing specific information for each state.)

Click to find specific information for each state
White students. The overall news is sobering. Some might try to comfort themselves by saying the problem is limited to large numbers of students from immigrant families, or to African American students and others who have suffered from discrimination. For example, the statement by the STEM Coalition that we “encourage more of our best and brightest students, especially those from underrepresented or disadvantaged groups, to study in STEM fields” suggests that the challenges are concentrated in nonwhite segments of the U.S. population.
Without denying that the paucity of high-achieving students within minority populations is a serious issue, let us consider the performance of white students for whom the case of discrimination cannot easily be made. Twenty-four countries have a larger percentage of highly accomplished students than the 8 percent achieving at that level among the U.S. white student population in the Class of 2009. Looking at just white students places the U.S. at a level equivalent to what all students are achieving in the United Kingdom, Hungary, and Poland. Seven percent of California’s white students are advanced, roughly the percentage for all Lithuanian students.
Children of parents with college degrees. Another possibility is that schools help students reach levels of high accomplishment if parents are providing the necessary support. To explore this possibility, we assumed that students who reported that at least one parent had graduated from college were likely to be given the kind of support that is needed for many to reach high levels of achievement. Approximately 45 percent of all U.S. students reported that at least one parent had a college degree.
The portion of students in the Class of 2009 with a college-graduate parent who are performing at the advanced level is 10.3 percent. When compared to all students in the other PISA countries, this advantaged segment of the U.S. population was outranked by students in 16 other countries. Nine percent of Illinois students with a college-educated parent scored at the advanced level, a percentage comparable to all students in France and the United Kingdom. The percentage of highly accomplished students from college-educated families in Rhode Island is just short of 6 percent, the same percentage for all students in Spain, Italy, and Latvia.
The Previous Rosy Gloss
Many casual observers may be surprised by our findings, as two previous, highly publicized studies have suggested that—even though improvement was possible—the U.S. was doing all right. This was the picture from two reports issued by Gary Phillips of the American Institutes for Research, who compared the average performance in math of 8th-grade students in each of the 50 states with the average scores of 8th-grade students in other countries. These comparisons used methods that are similar to ours to relate 2007 NAEP performance for U.S. students to both TIMSS 2003 and TIMSS 2007. His findings are more favorable to the United States than those shown by our analyses. While our study using the PISA data shows U.S. student performance in math to be below 30 other countries, Phillips found the average U.S. student to be performing better than all but 14 other countries in his 2007 report and all but 8 countries in his 2009 report. (Oddly, the 2007 report takes a much more buoyant perspective than the 2009 report, though the data suggest otherwise.) Phillips also finds that individual states do much better vis-à-vis other countries than we report.
Why do two studies that seem to be employing generally similar methodologies produce such strikingly different results?
The answer to that puzzle is actually quite simple and has little to do with the fact that Phillips compares average student performance while our study focuses on advanced students: many OECD countries, including those that had a high percentage of high-achieving students, participated in PISA 2006 (upon which our analysis is based) but did not participate in either TIMSS 2003 or TIMSS 2007, the two surveys included in the Phillips studies. In fact, 19 countries that outscored the U.S. on the PISA 2006 test did not participate in TIMSS 2003, and 22 higher-scoring countries did not participate in TIMSS 2007. As a report by the U.S. National Center for Education Statistics has explained, “Differences in the set of countries that participate in an assessment can affect how well the United States appears to do internationally when results are released.”
Put starkly, if one drops from a survey countries such as Canada, Denmark, Finland, France, Germany, and New Zealand, and includes instead such countries as Botswana, Ghana, Iran, and Lebanon, the average international performance will drop, and the United States will look better relative to the countries with which it is being compared.
Did NCLB shift the focus away from the best and the brightest?
Some attribute the comparatively small percentages of students performing at the advanced level to the focus of the 2002 federal accountability statute, No Child Left Behind, on the educational needs of very low performing students. That law mandates that every student be brought up to the level a state deems proficient, a standard that most states set well below NAEP’s proficient standard, to say nothing of the advanced level that is the focus of this report.
In order to comply with the federal law, some assert, schools are concentrating all available resources on the educationally deprived, leaving advanced students to fend for themselves. If so, then we should see a decline in the percentage of students performing at NAEP’s advanced level subsequent to the passage of the 2002 federal law. In mathematics, however, the opposite has happened. The percentage performing at the advanced level was only 3.7 percent in 1996 and 4.7 percent in the year 2000. But the percentage performing at an advanced level climbed steadily to the 7.9 percent attained in 2009.
Perhaps NCLB’s passage in 2002 dampened the prior rate of growth in the achievement of high-performing students. To ascertain whether that was the case, we compared the rate of change in the NAEP math scores of the top 10 percent of all 8th graders between 1990 and 2003 (before NCLB was fully implemented) with the rate of change after NCLB had become effective law. Between 1990 and 2003, the scores of students at the 90th percentile rose from 307 to 321, an increment of 14 points, or a growth rate of 1.0 points a year. Between 2003 and 2009, the shift upward for the 90th percentile was another 8 points, or a change of 1.3 points a year. Our results are confirmed by a more detailed study of NCLB’s impact on high-performing students conducted by economists Brian Jacob and Thomas Dee.
In short, the incapacity of American schools to bring students up to the highest level of accomplishment in mathematics is much more deepseated than anything induced by recent federal legislation.
Conclusions
The economic and technological demand for a talented, well-educated, highly skilled population has never been greater. Not only must everyday workers have a set of technical skills surpassing those needed in the past, but a cadre of highly talented professionals trained to the highest level of accomplishment is needed to foster innovation and growth. In the words of President Barack Obama, “Whether it’s improving our health or harnessing clean energy, protecting our security or succeeding in the global economy, our future depends on reaffirming America’s role as the world’s engine of scientific discovery and technological innovation. And that leadership tomorrow depends on how we educate our students today, especially in math, science, technology, and engineering.”
Unfortunately, the United States trails other industrialized countries in bringing a large proportion of its students up to the highest levels of accomplishment. This is not a story of some states doing well but being dragged down by states that perform poorly. Nor is it a story of immigrant or disadvantaged or minority students hiding the strong performance of better-prepared students. Comparatively small percentages of white students are high achievers. Only a small proportion of the children of our college-educated population is equipped to compete with students in a majority of OECD countries.
Major policy initiatives within the United States have in recent years focused on the educational needs of low-performing students. Such efforts deserve commendation, but they can leave the impression that there is no similar need to enhance the education of those students the STEM coalition has called “the best and brightest.” Yet, with rapidly advancing technologies in an increasingly integrated world economy, no one doubts the extraordinary importance of highly accomplished professionals.
Admittedly, the United States could simply ignore the needs of its own young people and continue to import highly skilled scientists and engineers who were prepared by better-performing schools abroad. But even such a heartless, irresponsible strategy relies on both the nature of immigration policies and the absence of better opportunities abroad, two things on which we might not want the future to depend. It seems much more prudent to encourage the most capable of our own people to reach high levels of academic accomplishment.
Eric A. Hanushek is senior fellow at the Hoover Institution of Stanford University. Paul E. Peterson is the director of Harvard’s Program on Education Policy and Governance and senior fellow at the Hoover Institution. Ludger Woessmann is professor of economics at the University of Munich.

Source: Educationnext.org
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Everyday math Long division



When starting division, you may be given simple division problems that you can do in your head, using mental math. Those problems would look like this:
You would think to yourself, what number times 9 gives me 27? And your answer would be 3. However, eventually you will encounter bigger division problems that you cannot do using mental math. In these cases, you will have to use long division.
For example, you might have a problem that looks like this:
You would re-write the problem so that it looks like this:
In this case, 5 is the divisor (the number we’re dividing by) and it goes on the outside of the division bar, as shown. 125 is the dividend (the number we’re dividing) and it goes on the inside of the division bar. The quotient (answer) will eventually sit on top of the division bar, when we’re done. Right now, the top of the division bar should be blank because we have not started yet.
Now, we can start our long division. There are four steps of long division; they are: divide, multiply, subtract, and bring down. Each step will be explained and shown in a different color in the step-by-step image.
Our first step of long division is to divide. In this step, we have to ask ourselves how many times the divisor goes into the first number of the dividend; or, in this case, we ask ourselves how many times we can put 5 into 1. You will notice that we cannot put 5 into 1, because 5 is bigger than one; thus, our first division results in 0. We write this number on top of the division bar, above the number we used (in this case, 1). Your problem so far looks like this:
Our next step of long division is to multiply. In this step, we multiply the divisor (5) by the answer we got to our division (in this case, 0). We multiply the two numbers together like this: 5 x 0 = 0. We write this number below the dividend, lining it up with the number we divided.
Our next step of long division is to subtract. In this step, we subtract our product (answer) from multiplication from the original number in the dividend. In this case, our problem would be 1 – 0 = 1. We would write the answer in the column we’ve now made (see diagram below).
Now we move on to our last step, which is to bring down. In order to bring down, we have to look at the next number in the dividend that we haven’t worked with yet; in this case, it’s 2. In order to bring down, we draw an arrow from the number in the dividend down to where we just ended our subtraction, and we write this number (2) next to the answer from our subtraction (1) to form a new number (12). This is shown in the diagram below.
Once you bring down the next number, you start this entire process over with division! In the image below, you’ll see the next set of steps performed, starting with this division question: how many times can we put 5 into 12? Follow along with the diagrams:
That was a complete step (division, multiplication, subtraction, and bringing down) that we just went through! We keep repeating the process until there are no more numbers to bring down. In this problem, we have one more complete step to go through before we get our answer. Here’s how to go through the last step:
Notice that when you went to bring down, there were no other numbers after the 5, so you had nothing to bring down. This means you are done! Your answer is the number that you have written on top of the division bar. For this problem, our answer is 25, and it is written in red on top of our division bar.
Some people like to have a way to remember the steps to long division, so they’ve come up with a saying to help you remember the order. The order is: Divide, Multiply, Subtract, Bring down. The saying is: Does McDonald’s Sell Burgers? The first letters of this saying match up with the first letters of the order of long division: D-M-S-B. If this helps you, feel free to use it to remember; if it confuses you, then don’t use it—just memorize the steps for long division.

Long Division Examples

Let’s go through one more example like this before we move on. Our new example is:
Let’s re-write the problem using the long division bar, and then follow the steps to long division (divide-multiply-subtract-bring down). Re-read the steps to the first problem if you’re still having trouble. Here’s the problem worked out:
Once again, our answer (quotient) is written above the division bar. Ours is written in red. Both of these problems had quotients of 25, but this will not always be the case! You could have any number as your quotient for a division problem.
When we have an answer for our division problem, it is easy to go back and check it. In order to check a division problem, you multiply the quotient (answer) by the divisor, and your product (answer to the multiplication problem) should be the same as the dividend.
Here’s the work for checking the last division problem:
We can see that our product, 100, is the same as the dividend, so we know we did our division correctly.
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Fun Math Games for Kids

 
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