Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 434 · 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. 1.714 − 667 =
2. 2.635 − 289 =
3. 3.750 − 607 =
4. 4.702 − 298 =
5. 5.726 − 699 =
6. 6.857 − 799 =
7. 7.513 − 487 =
8. 8.337 − 207 =
9. 9.493 − 299 =
10. 10.868 − 639 =
11. 11.947 − 698 =
12. 12.612 − 297 =
13. 13.923 − 258 =
14. 14.734 − 199 =
15. 15.358 − 129 =
16. 16.513 − 479 =
17. 17.629 − 599 =
18. 18.479 − 287 =
19. 19.811 − 197 =
20. 20.712 − 597 =
21. 21.937 − 238 =
22. 22.983 − 509 =
23. 23.813 − 689 =
24. 24.968 − 797 =
25. 25.660 − 399 =
26. 26.910 − 499 =
27. 27.936 − 498 =
28. 28.362 − 197 =
29. 29.793 − 297 =
30. 30.864 − 647 =
31. 31.880 − 597 =
32. 32.911 − 599 =
33. 33.720 − 199 =
34. 34.451 − 387 =
35. 35.575 − 349 =
36. 36.895 − 799 =
37. 37.873 − 697 =
38. 38.589 − 497 =
39. 39.688 − 498 =
40. 40.976 − 698 =

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