Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 33 · 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. 1.627 − 198 =
2. 2.667 − 599 =
3. 3.968 − 798 =
4. 4.598 − 397 =
5. 5.907 − 638 =
6. 6.357 − 278 =
7. 7.763 − 498 =
8. 8.597 − 268 =
9. 9.461 − 428 =
10. 10.740 − 187 =
11. 11.831 − 797 =
12. 12.792 − 598 =
13. 13.272 − 127 =
14. 14.765 − 177 =
15. 15.690 − 497 =
16. 16.602 − 448 =
17. 17.775 − 597 =
18. 18.435 − 399 =
19. 19.460 − 399 =
20. 20.958 − 797 =
21. 21.451 − 197 =
22. 22.842 − 697 =
23. 23.949 − 799 =
24. 24.985 − 397 =
25. 25.520 − 297 =
26. 26.852 − 799 =
27. 27.589 − 189 =
28. 28.498 − 117 =
29. 29.913 − 579 =
30. 30.764 − 358 =
31. 31.400 − 218 =
32. 32.600 − 218 =
33. 33.890 − 798 =
34. 34.590 − 197 =
35. 35.943 − 179 =
36. 36.881 − 469 =
37. 37.873 − 569 =
38. 38.785 − 699 =
39. 39.634 − 319 =
40. 40.828 − 697 =

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