Lesson 2

Strategies for Making Tens

Est. Class Sessions: 2

Daily Practice and Problems

Teacher Notes
X

TIMS Bit

These problems are grouped to encourage students to use doubles to find the answers. For example, 25 + 27 can be solved by doubling 25 and adding two.

(25 + 25 + 2 = 52)

  1. 12
  2. 11
  3. 14
  4. 100
  5. 110
  6. 105
  7. 50
  8. 52
  9. 40
  1. Possible strategy: Add two quarters to make 50 and then add the remaining 2 to make 52.

E. Mental Arithmetic Using Doubles

Solve these problems in your head. Write only the answers. Be ready to explain your answers.

  1. 6 + 6 =
  2. 6 + 5 =
  3. 8 + 6 =
  4. 50 + 50 =
  5. 60 + 50 =
  6. 50 + 55 =
  7. 25 + 25 =
  8. 25 + 27 =
  9. 25 + 15 =
  1. Show or tell how you solved Problem H.