Addition within 20 — Answer Key
Part A: Multiple Choice
Circle the correct answer for each question.
1. What is 9 + 4?
A) 11
B) 12
C) 13
D) 14
9 + 4 = 13. Make ten: 9 + 1 = 10, then 10 + 3 = 13.
2. What is 7 + 7?
A) 12
B) 13
C) 14
D) 15
7 + 7 = 14. This is a doubles fact.
3. Which addition makes 15?
A) 6 + 8
B) 7 + 8
C) 9 + 5
D) Both B and C
7 + 8 = 15 and 9 + 5 = 15. Both B and C equal 15.
4. To solve 8 + 5, you can make a ten. What is 8 + 2 + 3?
A) 12
B) 13
C) 14
D) 15
8 + 2 + 3 = 10 + 3 = 13. This is the 'make a ten' strategy for 8 + 5.
Part B: Fill in the Missing Number
Write the missing number to complete each number sentence.
1. 9 + 7 = 16
9 + 7 = 16. The missing addend is 9.
2. 8 + 9 = 17
8 + 9 = 17. The missing addend is 9.
3. 9 + 6 = 15
9 + 6 = 15. The missing addend is 9.
4. 10 + 9 = 19
10 + 9 = 19. The missing addend is 9.
5. 10 + 8 = 18
10 + 8 = 18. The missing addend is 10.