Lesson 8

Check It Out

Est. Class Sessions: 2

Daily Practice and Problems

Teacher Notes
X
  1. True
  2. False
  3. True
  4. False
  5. True
  6. True
  7. False
  8. False
  9. Possible response: I know 10 + 10 = 20 so one less is 19 and 9 is one less than 10 so 10 + 9 is also 19.

DD. True or False

  1. 6 + 7 = 6 + 6 + 1                     __________________
  2. 7 + 8 = 7 + 7 − 1                     __________________
  3. 10 + 9 = 10 + 10 − 1              __________________
  4. 15 − 8 = 8                                __________________
  5. 13 − 1 = 6 + 6                         __________________
  6. 8 + 8 = 18 − 2                         __________________
  7. 16 − 1 = 7 + 7                         __________________
  8. 19 − 9 = 9                                __________________
  9. Explain how you know your answer to Question C is correct.