Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 981 · 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. 1.631 − 397 =
2. 2.899 − 678 =
3. 3.686 − 497 =
4. 4.771 − 497 =
5. 5.618 − 407 =
6. 6.861 − 677 =
7. 7.962 − 798 =
8. 8.679 − 469 =
9. 9.646 − 158 =
10. 10.560 − 437 =
11. 11.988 − 797 =
12. 12.556 − 298 =
13. 13.600 − 549 =
14. 14.839 − 597 =
15. 15.372 − 147 =
16. 16.537 − 429 =
17. 17.641 − 508 =
18. 18.575 − 398 =
19. 19.541 − 508 =
20. 20.934 − 797 =
21. 21.646 − 298 =
22. 22.911 − 598 =
23. 23.625 − 517 =
24. 24.527 − 498 =
25. 25.538 − 268 =
26. 26.962 − 698 =
27. 27.862 − 649 =
28. 28.763 − 119 =
29. 29.774 − 347 =
30. 30.329 − 197 =
31. 31.919 − 607 =
32. 32.673 − 199 =
33. 33.559 − 418 =
34. 34.523 − 497 =
35. 35.349 − 199 =
36. 36.739 − 519 =
37. 37.922 − 397 =
38. 38.986 − 398 =
39. 39.361 − 169 =
40. 40.453 − 368 =

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