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Missing Addends Within 20

Grade 1 · Stretch challenge · 12 questions · Version PG-9AF7N-1OAJ

Four children and a teacher collaborate with blocks, patterns, and a notebook.
1.

__ + 2 = 20

2.

__ + 5 = 15

3.

__ + 5 = 20

4.

__ + 6 = 20

5.

__ + 11 = 20

6.

__ + 8 = 20

7.

__ + 12 = 18

8.

__ + 0 = 10

9.

__ + 2 = 12

10.

__ + 16 = 17

11.

__ + 3 = 20

12.

__ + 8 = 12

Answers and teaching notes

Use the answers to check the work after the learner finishes. For writing prompts, the guide describes what a strong response should include.

Show answers for version 20
  1. __ + 2 = 2018
  2. __ + 5 = 1510
  3. __ + 5 = 2015
  4. __ + 6 = 2014
  5. __ + 11 = 209
  6. __ + 8 = 2012
  7. __ + 12 = 186
  8. __ + 0 = 1010
  9. __ + 2 = 1210
  10. __ + 16 = 171
  11. __ + 3 = 2017
  12. __ + 8 = 124

Worked example

__ + 6 = 14. Think 14 - 6, so the missing addend is 8.

Common mistake

Adding the known addend and total together.

Helpful hint

Subtract the known part from the total.