図形の数
数学の概念
Products, divisibility, size of rectangles, areas
材料
小さな物を入れたボウル
Players の作成と管理
1〜4
セットアップ
Have a collection of 20 small, similar objects, such as Lego bricks.
再生する：
For each number, investigate which rectangles you can make with that many objects. 1 can only be made with a 1 by 1rectangle, and 1 is called a unit. The numbers, such as 5, that only have 1 by 5 and 5 by 1 rectangles, are called primes. Numbers that are not a unit or prime are called composite- they are called that because they are composed of primes being multiplied together, such as 12 = 2 x 2 x 3. Numbers such as 16 are called squares because one of their rectangles is a square– one rectangle for 16 is the 4 by 4 square.
議論とヒント
The dimensions of each rectangle are the values that evenly divide the number and multiply together to give the number. For example, rectangles for 10 objects are 1 by 10, 2 by 5, 5 by 2, and 1 by 10. 1, 2, 5, and 10 are the divisors of 10. Making rectangles is a direct way to experience divisibility.
For each number, have the group make a list of the sizes of the rectangles for it and a list of its divisors.