Lesson 2

The Coat of Many Bits

Est. Class Sessions: 3

Daily Practice and Problems

Teacher Notes
X

TIMS Bit

These problems can be solved in many ways. Ask students to describe their strategies, helping them verbalize their thinking. For example, for Question A, students can think addition with doubles. (Since 25 + 25 = 50, then 50 − 25 = 25.) Make sure number lines are available.

  1. 25
  2. 26
  3. 4
  4. 52
  5. 90
  6. 4
  7. 12
  8. 20
  1. Possible strategy: Students may count up from 48 to 50 and then use the double 50 + 50 to find the missing part.

G. Strategies for Subtraction Practice

Solve the following subtraction problems. Write only the answers. Be prepared to explain your strategies.

  1. 50 − 25 =
  2. 51 − 25 =
  3. 17 − 13 =
  4. 100 − 48 =
  5. 180 − 90 =
  6. 16 − 12 =
  7. 18 − 6 =
  8. 32 − 12 =
  1. Explain your strategy for Question D.