Teacher Notes
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TIMS Bit
Use this DPP item to practice using arrays to show all of the factors for 24 and for 30. This provides practice with the division facts for the 2s and 3s.
For each question, discuss which ways of cutting the cake would be best and why. Have students demonstrate for the class the various ways the cake can be cut. Have them use their drawings to justify their choices for the best way of cutting the cake. For example, 24 long skinny pieces (1 × 24) may be harder to cut than using a 4 × 6 array. Note that turn-around facts will result in the same pieces.
2 × 12 = 24
- 1 × 24 = 24
2 × 12 = 24
3 × 8 = 24
4 × 6 = 24
- 1 × 30 = 30
2 × 15 = 30
3 × 10 = 30
5 × 6 = 30
G. Multiplication Facts
Emma baked a cake. This square represents her cake.
- Show all the ways she can cut the cake if she wants to make 24 equal pieces that have the same shape. Draw a separate cake to show each way she can cut it. Write a multiplication number sentence to describe each way.
- Show all the ways she can cut the cake if she wants to make 30 pieces with the same size and shape. Draw all the possible ways she can cut the cake. Write a multiplication number sentence to describe each way.
