Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 579 · 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. 1.881 − 538 =
2. 2.594 − 357 =
3. 3.724 − 698 =
4. 4.893 − 139 =
5. 5.912 − 399 =
6. 6.314 − 279 =
7. 7.752 − 477 =
8. 8.824 − 679 =
9. 9.785 − 397 =
10. 10.676 − 429 =
11. 11.722 − 598 =
12. 12.986 − 597 =
13. 13.718 − 529 =
14. 14.925 − 697 =
15. 15.856 − 798 =
16. 16.886 − 278 =
17. 17.549 − 499 =
18. 18.829 − 797 =
19. 19.431 − 298 =
20. 20.944 − 198 =
21. 21.903 − 438 =
22. 22.614 − 258 =
23. 23.797 − 698 =
24. 24.870 − 199 =
25. 25.708 − 597 =
26. 26.778 − 398 =
27. 27.778 − 697 =
28. 28.700 − 199 =
29. 29.435 − 399 =
30. 30.625 − 598 =
31. 31.862 − 497 =
32. 32.377 − 247 =
33. 33.915 − 199 =
34. 34.953 − 697 =
35. 35.904 − 489 =
36. 36.997 − 798 =
37. 37.962 − 699 =
38. 38.924 − 168 =
39. 39.979 − 599 =
40. 40.584 − 497 =

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