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Missing Addends Within 20

Grade 1 · Stretch challenge · 12 questions · Version PG-151CC2V-1OAJ

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

__ + 10 = 14

2.

__ + 4 = 20

3.

__ + 10 = 15

4.

__ + 12 = 20

5.

__ + 13 = 16

6.

__ + 3 = 20

7.

__ + 12 = 16

8.

__ + 2 = 19

9.

__ + 2 = 12

10.

__ + 10 = 20

11.

__ + 9 = 20

12.

__ + 15 = 19

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 15
  1. __ + 10 = 144
  2. __ + 4 = 2016
  3. __ + 10 = 155
  4. __ + 12 = 208
  5. __ + 13 = 163
  6. __ + 3 = 2017
  7. __ + 12 = 164
  8. __ + 2 = 1917
  9. __ + 2 = 1210
  10. __ + 10 = 2010
  11. __ + 9 = 2011
  12. __ + 15 = 194

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.