Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 25 · 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. 1.894 − 798 =
2. 2.674 − 297 =
3. 3.735 − 398 =
4. 4.832 − 797 =
5. 5.840 − 447 =
6. 6.971 − 429 =
7. 7.991 − 219 =
8. 8.710 − 549 =
9. 9.681 − 197 =
10. 10.961 − 557 =
11. 11.845 − 558 =
12. 12.289 − 239 =
13. 13.981 − 499 =
14. 14.710 − 497 =
15. 15.865 − 299 =
16. 16.690 − 398 =
17. 17.543 − 499 =
18. 18.649 − 297 =
19. 19.780 − 597 =
20. 20.507 − 197 =
21. 21.438 − 199 =
22. 22.804 − 557 =
23. 23.538 − 478 =
24. 24.926 − 697 =
25. 25.792 − 498 =
26. 26.807 − 498 =
27. 27.313 − 247 =
28. 28.886 − 387 =
29. 29.761 − 488 =
30. 30.862 − 698 =
31. 31.918 − 668 =
32. 32.508 − 397 =
33. 33.346 − 268 =
34. 34.688 − 199 =
35. 35.487 − 279 =
36. 36.744 − 439 =
37. 37.931 − 588 =
38. 38.943 − 248 =
39. 39.720 − 497 =
40. 40.916 − 437 =

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