# Featured

## One Grain of Rice: Power of Doubling (9.23.10 Kindergarten)

Many years ago, there lived a selfish raja in India. He ruled that all

the people should give him almost all of their rice for safekeeping,

so that in a time of need there would be rice to eat. One year, a

## Cube-ometry (9.20.10--9.23.10 1st through 5th Grade)

Welcome to the seventh year of Mathletes 2010-2011!

The children created cubes (or regular hexahedron) from square pieces of paper. First we explored the wonderful properties of a cube:

## Prime Numbers using the Sieve of Eratosthenes (May 19th thru May 24th)

In ancient Greece around 250BC, Eratosthenes, a Greek mathematician devised a simple way of finding primes under 10 million. He would simply eliminate all of the numbers that were not prime, starting with 1. Then he would cirlce the first prime (2) and then cross out all of the even numbers or multiples of the prime he circled. Then he would circle the next prime (3) and cross out all of its multiples (of course, half of the multiples of 3 would already be crossed out since they were also multiples of 2). He would then move to 5, and so on.

## Factoring Game (May 11 thru May 17)

This is a game similar to chess as there is no chance. You always have to calculate the best move. It teaches you strategy, factoring, subtraction, and at the end, long addition (also, the sum of an arithmetic sequence -- can you figure out why?)

## Pentominoes (May 4 thru May 10)

Polyominoes is the general name given to plane shapes made by joining squares together. Note that the squares must be 'properly' joined edge to edge so that they meet at the corners. Each type of polyomino is named according to how many squares are used to make it. So there are monominoes (1 square only), dominoes (2 squares), triominoes (3 squares), tetrominoes (4 squares), pentominoes (5 squares), hexominoes (6 squares) and so on.