Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 934 · 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. 1.443 − 179 =
2. 2.775 − 298 =
3. 3.816 − 519 =
4. 4.651 − 497 =
5. 5.938 − 799 =
6. 6.945 − 238 =
7. 7.910 − 297 =
8. 8.983 − 469 =
9. 9.835 − 797 =
10. 10.375 − 198 =
11. 11.846 − 499 =
12. 12.501 − 478 =
13. 13.908 − 148 =
14. 14.988 − 497 =
15. 15.551 − 199 =
16. 16.816 − 497 =
17. 17.824 − 397 =
18. 18.482 − 197 =
19. 19.645 − 397 =
20. 20.714 − 498 =
21. 21.456 − 129 =
22. 22.605 − 267 =
23. 23.857 − 799 =
24. 24.774 − 699 =
25. 25.897 − 197 =
26. 26.864 − 797 =
27. 27.995 − 629 =
28. 28.958 − 698 =
29. 29.905 − 478 =
30. 30.946 − 237 =
31. 31.797 − 547 =
32. 32.835 − 598 =
33. 33.464 − 297 =
34. 34.837 − 279 =
35. 35.981 − 599 =
36. 36.624 − 598 =
37. 37.847 − 427 =
38. 38.749 − 399 =
39. 39.792 − 697 =
40. 40.694 − 299 =

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