This medium worksheet challenges first graders to find missing numbers in subtraction sentences within 20. Nine fill-in-the-blank problems mix different unknown positions, such as '___ - 4 = 7' and '16 - ___ = 9,' plus count-back prompts like 'Start at 15.' A matching activity then pairs four subtraction expressions (15 - 7, 18 - 9, 14 - 8, 20 - 13) with their answers, helping children build flexible thinking and connect related facts.
Style:
Subtraction Within 20
Part A: Fill in the Missing Number
Write the missing number to complete each subtraction sentence.
1. 11 - 4 = 7
2. 16 - 7 = 9
3. Start at 15. Count back 6. You land on 9.
4. 20 - 8 = 12
5. 17 - 8 = 9
6. Start at 18. Count back 7. You land on 11.
7. If 8 + 6 = 14, then 14 - 6 = 8.
8. 13 - 8 = 5
9. If 9 + 5 = 14, then 14 - 5 = 9.
Part B: Match the Problem to Its Answer
Draw a line from each subtraction problem to its correct answer.
1. Match each subtraction problem to its answer.
15 - 7
→ 8
9
18 - 9
→ 9
7
14 - 8
→ 6
6
20 - 13
→ 7
8
Subtraction Within 20
★ Part A: Fill in the Missing Number
Write the missing number to complete each subtraction sentence.
1) 11 - 4 = 7
2) 16 - 7 = 9
3) Start at 15. Count back 6. You land on 9.
4) 20 - 8 = 12
5) 17 - 8 = 9
6) Start at 18. Count back 7. You land on 11.
7) If 8 + 6 = 14, then 14 - 6 = 8.
8) 13 - 8 = 5
9) If 9 + 5 = 14, then 14 - 5 = 9.
★ Part B: Match the Problem to Its Answer
Draw a line from each subtraction problem to its correct answer.
1) Match each subtraction problem to its answer.
15 - 7
→ 8
9
18 - 9
→ 9
7
14 - 8
→ 6
6
20 - 13
→ 7
8
Ready to Practice?
For Part A, write the missing number. For Part B, match each problem to its answer.
10 Questions
15-20 minutes
Auto-graded
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