Addition within 10 — Answer Key
Part A: Fill in the Missing Number
Write the missing number to complete each number sentence.
1. 2 + 6 = 8
To find the missing number, subtract 2 from 8: 8 - 2 = 6, so 2 + 6 = 8.
2. 5 + 5 = 10
To find the missing number, subtract 5 from 10: 10 - 5 = 5, so 5 + 5 = 10.
3. 4 + 3 = 7
To find the missing number, subtract 4 from 7: 7 - 4 = 3, so 4 + 3 = 7.
4. 3 + 6 = 9
To find the missing number, subtract 6 from 9: 9 - 6 = 3, so 3 + 6 = 9.
5. 7 + 3 = 10
To find the missing number, subtract 7 from 10: 10 - 7 = 3, so 7 + 3 = 10.
6. 7 + 1 = 8
To find the missing number, subtract 1 from 8: 8 - 1 = 7, so 7 + 1 = 8.
7. 5 + 2 = 7
To find the missing number, subtract 5 from 7: 7 - 5 = 2, so 5 + 2 = 7.
8. 6 + 3 = 9
To find the missing number, subtract 3 from 9: 9 - 3 = 6, so 6 + 3 = 9.
9. 0 + 10 = 10
To find the missing number, subtract 0 from 10: 10 - 0 = 10, so 0 + 10 = 10.
Part B: Match the Equation to Its Answer
Draw a line to match each addition problem to its answer.
1.
3 + 5
→ 8
9
4 + 4
→ 8
8
1 + 8
→ 9
8
6 + 3
→ 9
9
Add to find each sum: 3 + 5 = 8, 4 + 4 = 8, 1 + 8 = 9, and 6 + 3 = 9. Two problems make 8 and two problems make 9.