Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 325 · 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. 1.537 − 218 =
2. 2.926 − 398 =
3. 3.579 − 497 =
4. 4.418 − 269 =
5. 5.350 − 199 =
6. 6.918 − 369 =
7. 7.745 − 469 =
8. 8.879 − 799 =
9. 9.638 − 199 =
10. 10.635 − 498 =
11. 11.565 − 149 =
12. 12.832 − 518 =
13. 13.688 − 507 =
14. 14.417 − 298 =
15. 15.760 − 698 =
16. 16.431 − 309 =
17. 17.583 − 539 =
18. 18.606 − 299 =
19. 19.199 − 119 =
20. 20.361 − 298 =
21. 21.776 − 207 =
22. 22.780 − 608 =
23. 23.699 − 647 =
24. 24.719 − 667 =
25. 25.863 − 159 =
26. 26.986 − 598 =
27. 27.814 − 538 =
28. 28.893 − 499 =
29. 29.791 − 128 =
30. 30.876 − 798 =
31. 31.946 − 799 =
32. 32.762 − 269 =
33. 33.677 − 398 =
34. 34.825 − 629 =
35. 35.350 − 297 =
36. 36.655 − 557 =
37. 37.511 − 299 =
38. 38.909 − 798 =
39. 39.855 − 198 =
40. 40.760 − 687 =

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