Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 924 · 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. 1.933 − 627 =
2. 2.191 − 149 =
3. 3.640 − 599 =
4. 4.734 − 698 =
5. 5.690 − 198 =
6. 6.664 − 549 =
7. 7.907 − 798 =
8. 8.629 − 418 =
9. 9.532 − 348 =
10. 10.663 − 497 =
11. 11.275 − 199 =
12. 12.548 − 479 =
13. 13.972 − 299 =
14. 14.578 − 498 =
15. 15.607 − 497 =
16. 16.773 − 579 =
17. 17.685 − 658 =
18. 18.602 − 499 =
19. 19.711 − 469 =
20. 20.993 − 558 =
21. 21.920 − 679 =
22. 22.790 − 129 =
23. 23.751 − 149 =
24. 24.918 − 398 =
25. 25.698 − 277 =
26. 26.783 − 598 =
27. 27.723 − 697 =
28. 28.788 − 358 =
29. 29.853 − 599 =
30. 30.232 − 199 =
31. 31.790 − 597 =
32. 32.255 − 119 =
33. 33.167 − 118 =
34. 34.883 − 367 =
35. 35.682 − 297 =
36. 36.730 − 497 =
37. 37.957 − 598 =
38. 38.531 − 399 =
39. 39.750 − 168 =
40. 40.715 − 497 =

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