Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 890 · 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. 1.314 − 298 =
2. 2.740 − 297 =
3. 3.586 − 527 =
4. 4.535 − 397 =
5. 5.831 − 499 =
6. 6.788 − 598 =
7. 7.860 − 199 =
8. 8.911 − 699 =
9. 9.896 − 618 =
10. 10.620 − 199 =
11. 11.833 − 647 =
12. 12.629 − 599 =
13. 13.226 − 199 =
14. 14.767 − 597 =
15. 15.951 − 699 =
16. 16.567 − 499 =
17. 17.958 − 657 =
18. 18.682 − 499 =
19. 19.963 − 128 =
20. 20.888 − 799 =
21. 21.528 − 469 =
22. 22.829 − 698 =
23. 23.873 − 799 =
24. 24.836 − 688 =
25. 25.807 − 698 =
26. 26.894 − 797 =
27. 27.651 − 579 =
28. 28.539 − 498 =
29. 29.657 − 599 =
30. 30.453 − 437 =
31. 31.424 − 199 =
32. 32.835 − 498 =
33. 33.546 − 307 =
34. 34.483 − 297 =
35. 35.969 − 598 =
36. 36.303 − 198 =
37. 37.936 − 448 =
38. 38.975 − 289 =
39. 39.941 − 199 =
40. 40.744 − 298 =

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