Addition Within 20 — Answer Key
Part A: Multiple Choice
Circle the correct answer for each question.
1. On a number line, you start at 8 and jump 7 spaces forward. Where do you land?
A) 14
B) 15
C) 16
D) 17
B is correct because starting at 8 and jumping 7 on the number line lands on 15.
2. Anna has 9 stickers. She gets 8 more. How many stickers does she have now?
A) 15
B) 16
C) 17
D) 18
C is correct because 9 + 8 = 17 stickers in all.
3. Which two numbers add up to 20?
A) 7 + 12
B) 8 + 11
C) 9 + 11
D) 6 + 13
C is correct because 9 + 11 = 20, while A = 19, B = 19, and D = 19.
4. To solve 6 + 8, you start at 8 on the number line. How many jumps forward do you make?
A) 5
B) 6
C) 7
D) 8
B is correct because you jump 6 times from 8 to reach 14.
Part B: Fill in the Missing Number
Use the number line to find the missing number. Write it on the line.
1. 9 + 9 = 18
To find the missing number, subtract 9 from 18: 18 - 9 = 9, so 9 + 9 = 18.
2. 7 + 9 = 16
To find the missing number, subtract 7 from 16: 16 - 7 = 9, so 7 + 9 = 16.
3. 12 + 8 = 20
To find the missing number, subtract 8 from 20: 20 - 8 = 12, so 12 + 8 = 20.
4. 13 + 6 = 19
To find the missing number, subtract 13 from 19: 19 - 13 = 6, so 13 + 6 = 19.
5. 7 + 7 = 14
To find the missing number, subtract 7 from 14: 14 - 7 = 7, so 7 + 7 = 14.