Lesson 3

Spinning Sums

Est. Class Sessions: 2–3

Daily Practice and Problems

Teacher Notes
X

TIMS Task

Ask a student to show how to solve each problem using the class number line. Emphasize strategies that involve using tens or making tens.

  1. 22
  2. 19
  3. 28
  4. 27
  5. 28
  6. 30
  1. Possible response:
    16 + 8 + 4 = 16 + 4 + 8 = 28

I switch the 8 and 4 so I can add 16 + 4. I know 6 + 4 = 10, so 16 + 4 = 20. 20 + 8 = 28.

Ongoing Assessment

Use DPP Task L to assess students' abilities to use the using-tens strategy to solve an addition problem [E5].

L. Three Addends

Use mental math strategies to solve the following.

  1. 5 + 12 + 5 =
  2. 7 + 9 + 3 =
  3. 8 + 14 + 6 =
  4. 9 + 7 + 11 =
  5. 16 + 8 + 4 =
  6. 13 + 9 + 8 =
  1. Show or tell how you solved Problem E.