# Featured

## Multiplying by Eleven and Eleven Divisibility (Oct. 19 - 25)

**Multiplying by 11**

The skill set this reinforces is simple addition but within seconds we end up with the product of any number and 11.

First, students write down any number of any number of digits.

Second, they repeat the number below the first but move the number to the left one "place." The ones digit of the second number is directly below the tens digit of the first number.

Third, the students add the two numbers.

## Pythagorean Right Triangles (10-12 through 10-18)

We continued our exploration of squares by introducing the greatest theorem in the history of mathematics -- the Pythagorean Theorem: the sum of the squares of the legs of a right triangle will equal the square of the hypotenuse. We used our 3x3 and 4x4 and 5x5 square of tennis balls to show the most simple Pythagorean triple, a 3-4-5 triangle.

## Anti-Number Pairs (Kindergarten 10-14-10)

This week we introduced anti-numbers like anti-tens. The "anti-ten" of 3 is 7; the "anti-ten" of 4 is 6 and so on.

We gave the children several anti-numbers to challenge them to understand friendly numbers and important pairs. For example, they should know their anti-nines and frankly any anti-prime number.

See the attached pdf for easy to use worksheets.

## It is good to be SQUARE (Oct. 4-7, 2010)

This week's goal is to become one with squares. Mathletes should challenge themselves to learn the first10 squares; maybe the first 15 squares; if really ambitious, the first 20 squares. Knowledge of the first 24 squares makes every math students stronger in all disciplines, including addition, subtraction, multiplication, division, quadratics, and cubics. See the attached pdf.

## Isometric Drawings:3 Drawings (9-27-10 through 9-30-10)

Some Mathletes created one cube and some dozens, some small and some huge (one was 64 times the volume of the standard size).

The children created buildings with their cubes with dimensions no more than 4x4x4 and then learned how architects use Front, Top, and Side views to communicate their creations to the builders. The attached power point will take you through these exercises. Also, starting on page 11 of the powerpoint, we gave them three view drawings and they had to create the buildings as if they were the builder reading architectural drawings.