Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 855 · 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. 1.670 − 147 =
2. 2.621 − 499 =
3. 3.624 − 599 =
4. 4.680 − 169 =
5. 5.930 − 499 =
6. 6.820 − 577 =
7. 7.531 − 198 =
8. 8.421 − 297 =
9. 9.884 − 497 =
10. 10.770 − 299 =
11. 11.549 − 249 =
12. 12.541 − 448 =
13. 13.627 − 148 =
14. 14.794 − 397 =
15. 15.881 − 299 =
16. 16.973 − 797 =
17. 17.902 − 558 =
18. 18.748 − 398 =
19. 19.840 − 339 =
20. 20.431 − 199 =
21. 21.828 − 478 =
22. 22.851 − 398 =
23. 23.675 − 319 =
24. 24.527 − 498 =
25. 25.463 − 217 =
26. 26.454 − 228 =
27. 27.863 − 299 =
28. 28.923 − 229 =
29. 29.416 − 298 =
30. 30.597 − 349 =
31. 31.507 − 198 =
32. 32.363 − 297 =
33. 33.861 − 699 =
34. 34.780 − 299 =
35. 35.998 − 387 =
36. 36.829 − 199 =
37. 37.715 − 687 =
38. 38.997 − 509 =
39. 39.942 − 689 =
40. 40.729 − 698 =

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