Let’s solve each subtraction problem using the number line method.
We start at the first number (the minuend), then move left by the second number (the subtrahend) to find the answer.
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1. 15 - 5
Start at 15. Move 5 steps left:
14, 13, 12, 11,
10 → Answer:
10
2. 18 - 8
Start at 18. Move 8 steps left:
17, 16, 15, 14, 13, 12, 11,
10 → Answer:
10
3. 11 - 1
Start at 11. Move 1 step left:
→
10 → Answer:
10
4. 14 - 4
Start at 14. Move 4 steps left:
13, 12, 11,
10 → Answer:
10
5. 19 - 9
Start at 19. Move 9 steps left:
18, 17, 16, 15, 14, 13, 12, 11,
10 → Answer:
10
6. 12 - 2
Start at 12. Move 2 steps left:
11,
10 → Answer:
10
7. 17 - 7
Start at 17. Move 7 steps left:
16, 15, 14, 13, 12, 11,
10 → Answer:
10
8. 13 - 3
Start at 13. Move 3 steps left:
12, 11,
10 → Answer:
10
9. 16 - 6
Start at 16. Move 6 steps left:
15, 14, 13, 12, 11,
10 → Answer:
10
10. 20 - 10
Start at 20. Move 10 steps left:
19, 18, 17, 16, 15, 14, 13, 12, 11,
10 → Answer:
10
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All problems result in
10. This is a pattern — each problem subtracts a number that leaves exactly 10 when taken from the starting number.
Final Answer:
10
10
10
10
10
10
10
10
10
10
Parent Tip: Review the logic above to help your child master the concept of subtraction worksheet for 1st grade with number line.
