Lesson 2

Collect Pet Data

Est. Class Sessions: 2–3

Daily Practice and Problems

Teacher Notes
X

Students can verify their answers using cubes, number lines, or ten frames. DPP item E provides practice with the addition and related subtraction facts in Group C.

    1. 2 + 8 = 10
    2. 3 + 8 = 11
    3. 4 + 8 = 12

2 + 8 = 10. 3 is one more than 2, so 3 + 8 is one more than 10, or 11. 4 is two more than 2, so 4 + 8 is 2 more than 10, or 12.

    1. 11 − 2 = 9
    2. 11 − 3 = 8
    3. 11 − 4 = 7

11 − 2 = 9. 3 takes away one more than 2, so 11 − 3 is 8. 4 takes away two more than 2, so 11 − 4 is 7.

  1. Possible response: I know 8 + 3 = 11, so 11 − 3 is 8. I think about fact families.

E. Facts and Patterns 1

How can you use the top fact to solve the two related facts under it?

  1. A. 2 + 8 = _____

    B. 3 + 8 = _____

    C. 4 + 8 = _____

  2. A. 11 − 2 = _____

    B. 11 − 3 = _____

    C. 11 − 4 = _____

  1. How does knowing 3 + 8 help you solve 11 − 3?