Addition Within 20 — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. What is 5 + 8?
A) 11
B) 12
C) 13
D) 14
Make a ten: 8 + 2 = 10, then 10 + 3 = 13.
2. What is 9 + 9?
A) 16
B) 17
C) 18
D) 19
9 + 9 = 18. This is a doubles fact: 9 doubled is 18.
3. What is 4 + 9?
A) 11
B) 12
C) 13
D) 14
Make a ten: 9 + 1 = 10, then 10 + 3 = 13.
4. What is 7 + 6?
A) 12
B) 13
C) 14
D) 15
Make a ten: 7 + 3 = 10, then 10 + 3 = 13.
Part B: Fill in the Blank
Write the correct answer on each line.
1. 11 + 6 = 17
Think: what number plus 6 equals 17? Since 11 + 6 = 17, the missing number is 11.
2. 9 + 6 = 15
Think: 9 plus what number equals 15? Since 9 + 6 = 15, the missing number is 6.
3. 11 + 4 = 15
Think: what number plus 4 equals 15? Since 11 + 4 = 15, the missing number is 11.
4. 8 + 6 = 14
Think: 8 plus what number equals 14? Since 8 + 6 = 14, the missing number is 6.
5. 9 + 9 = 18
Think: what number plus 9 equals 18? Since 9 + 9 = 18, the missing number is 9.