This is a level 3 number activity from the Figure It Out series. It relates to Stage 6 of the Number Framework.
use arrays to solve multiplication facts
This activity shows students another model for multiplication, that is, that multiplication can be shown as a rectangular array. Making chocolate bar rectangles reinforces the commutative property of multiplication (a x b = b x a). This activity also shows that multiplication can be used to find the area of a rectangle. (This connects to the measurement strand.)
This activity will help students find the factors for a given product. The set of factors for 12 (1, 2, 3, 4, 6, and 12) can be found from the three different lengths of the chocolate blocks.
As an extension, you could ask students to imagine the chocolate blocks as squares and encourage them to find all square numbers from one to 100.
Answers to Activity
a. 1 x 18; 2 x 9; 3 x 6
b. 1 x 25; 5 x 5
c. 1 x 36; 2 x 18; 3 x 12; 4 x 9; 6 x 6
d. 1 x 100; 2 x 50; 4 x 25; 5 x 20; 10 x 10