Addition Within 10 — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. 4 + 5 = 9
Since 4 + 5 = 9, the missing number is 5.
2. 5 + 3 = 8
Since 5 + 3 = 8, the missing number is 5.
3. 6 + 2 = 8
Counting on two more from 6 lands on 8, so 6 + 2 = 8.
4. 1 + 6 = 7
Since 1 + 6 = 7, the missing number is 6.
5. 0 + 4 = 4
Adding zero keeps a number the same, so 0 + 4 = 4 and the missing number is 0.
6. 3 + 7 = 10
Putting 3 and 7 together makes a ten: 3 + 7 = 10.
7. 5 + 1 = 6
Since 5 + 1 = 6, the missing number is 1.
8. 3 + 2 = 5
Since 3 + 2 = 5, the missing number is 3.
9. 2 + 2 = 4
Doubling 2 gives 4, because 2 + 2 = 4.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
5 + 4
→ 9
6
3 + 3
→ 6
10
1 + 9
→ 10
7
2 + 5
→ 7
9
Each addition fact pairs with its sum: 5 + 4 makes 9, 3 + 3 makes 6, 1 + 9 makes 10, and 2 + 5 makes 7.