Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 653 · 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. 1.866 − 598 =
2. 2.627 − 199 =
3. 3.784 − 689 =
4. 4.659 − 298 =
5. 5.857 − 499 =
6. 6.631 − 199 =
7. 7.228 − 197 =
8. 8.991 − 177 =
9. 9.919 − 597 =
10. 10.347 − 188 =
11. 11.706 − 669 =
12. 12.638 − 497 =
13. 13.848 − 299 =
14. 14.782 − 698 =
15. 15.790 − 297 =
16. 16.907 − 519 =
17. 17.817 − 599 =
18. 18.971 − 398 =
19. 19.870 − 479 =
20. 20.228 − 167 =
21. 21.717 − 628 =
22. 22.880 − 797 =
23. 23.546 − 197 =
24. 24.989 − 597 =
25. 25.630 − 299 =
26. 26.908 − 468 =
27. 27.804 − 599 =
28. 28.865 − 499 =
29. 29.810 − 497 =
30. 30.324 − 197 =
31. 31.822 − 639 =
32. 32.859 − 797 =
33. 33.833 − 598 =
34. 34.696 − 599 =
35. 35.732 − 359 =
36. 36.889 − 269 =
37. 37.926 − 307 =
38. 38.882 − 209 =
39. 39.370 − 288 =
40. 40.707 − 499 =

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