Lesson 1

Time to the Nearest Five Minutes

Est. Class Sessions: 2–3

Daily Practice and Problems

Teacher Notes
X

TIMS Bit

This Bit involves the subtraction facts in Group 7. Students are usually quite comfortable with addition “doubles.” The facts in this group can be solved by “thinking addition” with doubles (14 − 7 = 7 because 7 + 7 = 14). Students can also use doubles to figure out “near doubles” such as 14 − 6 = 8.

  1. 7
  2. 8
  3. 6
  4. 6
  5. 5
  6. 7
  7. 50
  8. 6
  9. 7
  1. Possible strategy: Students can use the subtraction fact 12 − 6 = 6 to reason that 12 − 5 will be one more or 7 (12 − 5 = 7).

C. Subtraction: Using Doubles

Do these problems in your head. Write only the answers.

  1. 14 − 7 =
  2. = 14 − 6
  3. 14 − 8 =
  4. = 12 − 6
  5. = 12 − 7
  6. 12 − 5 =
  7. 100 − 50 =
  8. = 13 − 7
  9. 13 − 6 =
  1. Explain your strategy for solving Question F.