# Featured

## 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.

## MCAS Best Practices (April 13 thru May 3)

We spent the last two weeks reviewing Best Practices for the math MCAS in preparation for the upcoming exams to be given the second week in May.

We even had the first and second graders work on the 3rd Grade test as appropriate for them. They definitely rose to the occasion.

The first week of this unit, we had the children take the 3rd, 4th or 5th grade MCAS test given Spring 2009. If they completed it in class or brought it to the following class, I graded it and had them correct all incorrect responses.