Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 178 · 40 questions

How to do it in your head (Round up, add back): Round the number you take away up to the next ten or hundred: 297 → 300 (3 too many). Take away the round number. Add back the extra, because you took away too much.

1. 1.784 − 467 =
2. 2.616 − 499 =
3. 3.767 − 117 =
4. 4.720 − 198 =
5. 5.709 − 599 =
6. 6.982 − 797 =
7. 7.930 − 598 =
8. 8.632 − 398 =
9. 9.757 − 499 =
10. 10.978 − 178 =
11. 11.848 − 797 =
12. 12.571 − 477 =
13. 13.743 − 217 =
14. 14.898 − 548 =
15. 15.992 − 797 =
16. 16.493 − 198 =
17. 17.577 − 139 =
18. 18.825 − 597 =
19. 19.723 − 299 =
20. 20.800 − 239 =
21. 21.985 − 599 =
22. 22.938 − 797 =
23. 23.733 − 418 =
24. 24.967 − 497 =
25. 25.949 − 267 =
26. 26.859 − 467 =
27. 27.817 − 198 =
28. 28.806 − 408 =
29. 29.281 − 199 =
30. 30.745 − 129 =
31. 31.152 − 118 =
32. 32.484 − 239 =
33. 33.641 − 458 =
34. 34.580 − 497 =
35. 35.528 − 497 =
36. 36.491 − 387 =
37. 37.948 − 298 =
38. 38.969 − 497 =
39. 39.818 − 799 =
40. 40.760 − 397 =

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