Subtraction Within 20 (Regrouping) — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. 11 - 5 = 6
Take 1 off to reach 10 (11 - 1 = 10), then remove 4 more to land on 6.
2. 14 - 7 = 7
This is a doubles fact: since 7 + 7 = 14, taking 7 away from 14 leaves 7.
3. 16 - 8 = 8
Doubles again: 8 + 8 = 16, so 16 - 8 must be 8.
4. 13 - 4 = 9
Break 4 into 3 and 1: 13 - 3 = 10, then 10 - 1 = 9.
5. 17 - 9 = 8
Because 9 + 8 = 17, the difference between 17 and 9 has to be 8.
6. 12 - 6 = 6
Doubles: 6 + 6 = 12, so subtracting one 6 from 12 leaves the other 6.
7. 15 - 7 = 8
Split 7 into 5 and 2: 15 - 5 = 10, then 10 - 2 = 8.
8. 18 - 9 = 9
This is a doubles fact — 9 + 9 = 18 — so the leftover after taking 9 away is 9.
9. 11 - 8 = 3
Count up from 8 to 11: 9, 10, 11 — that is 3 steps, so 11 - 8 = 3.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
13 - 7
→ 6
5
14 - 9
→ 5
6
12 - 3
→ 9
8
16 - 8
→ 8
9
Use partner pairs to match each one: 7 + 6 = 13, 9 + 5 = 14, 3 + 9 = 12, and 8 + 8 = 16.