Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 701 · 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. 1.681 − 197 =
2. 2.845 − 799 =
3. 3.599 − 307 =
4. 4.537 − 318 =
5. 5.439 − 209 =
6. 6.470 − 389 =
7. 7.586 − 448 =
8. 8.841 − 698 =
9. 9.614 − 567 =
10. 10.700 − 669 =
11. 11.810 − 599 =
12. 12.952 − 498 =
13. 13.837 − 409 =
14. 14.452 − 357 =
15. 15.829 − 798 =
16. 16.860 − 499 =
17. 17.685 − 199 =
18. 18.733 − 689 =
19. 19.604 − 199 =
20. 20.976 − 798 =
21. 21.656 − 598 =
22. 22.466 − 299 =
23. 23.563 − 519 =
24. 24.615 − 158 =
25. 25.872 − 597 =
26. 26.559 − 478 =
27. 27.842 − 647 =
28. 28.996 − 399 =
29. 29.782 − 187 =
30. 30.483 − 379 =
31. 31.328 − 298 =
32. 32.890 − 599 =
33. 33.363 − 298 =
34. 34.968 − 197 =
35. 35.729 − 207 =
36. 36.625 − 599 =
37. 37.703 − 528 =
38. 38.664 − 628 =
39. 39.741 − 257 =
40. 40.828 − 399 =

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