Lesson 1

Eyelets Lab

Est. Class Sessions: 3–4

Daily Practice and Problems

Teacher Notes
X

TIMS Bit

  1. 5
  2. 95
  3. 3
  4. 5
  5. 20
  6. 56
  7. 205
  8. 83
  9. 800
  10. Possible response: I know 99 + 1 = 100 and 104 is 4 more so, 1 + 4 = 5.

A. Using Mental Math to Add and Subtract

Do these problems in your head.

    1. 34 + N = 39
    2. N = _______________
    1. 50 + 45 = N
    2. N = _______________
    1. 89 + N = 92
    2. N = _______________
    1. 104 − N = 99
    2. N = _______________
    1. N + 128 = 148
    2. N = _______________
    1. 210 + N = 266
    2. N = _______________
    1. N − 105 = 100
    2. N = _______________
    1. N − 40 = 43
    2. N = _______________
    1. 919 − N = 119
    2. N = _______________
  10. Show or tell how you solved Question D. What did you do in your head?