Lesson 8

3-D to 2-D

Est. Class Sessions: 2

Teacher Notes

Use this DPP item to practice using 10s to solve multiplication facts for 9s.

Possible response: I do not agree with Joe because 7 × 10 = 70. If you subtract 70 − 7 the answer is 63 not 62.
10 × 6 = 60 and 60 − 6 = 54, so 9 × 6 = 54

Moe said, “I know 9 × 8 because I know that 10 × 8 = 80 and since 9 is one less than ten, 9 × 8 = 10 × 8 − 8. So, 9 × 8 = 80 − 8 = 72.”

Joe said, “9 × 7 = 62.”