Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 431 · 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. 1.966 − 358 =
2. 2.716 − 258 =
3. 3.849 − 618 =
4. 4.697 − 138 =
5. 5.820 − 797 =
6. 6.979 − 799 =
7. 7.350 − 198 =
8. 8.742 − 699 =
9. 9.478 − 368 =
10. 10.410 − 169 =
11. 11.778 − 498 =
12. 12.815 − 799 =
13. 13.819 − 797 =
14. 14.978 − 507 =
15. 15.708 − 497 =
16. 16.540 − 299 =
17. 17.589 − 259 =
18. 18.922 − 798 =
19. 19.533 − 298 =
20. 20.783 − 539 =
21. 21.745 − 199 =
22. 22.951 − 229 =
23. 23.380 − 198 =
24. 24.795 − 639 =
25. 25.530 − 298 =
26. 26.806 − 597 =
27. 27.692 − 159 =
28. 28.915 − 698 =
29. 29.737 − 698 =
30. 30.419 − 398 =
31. 31.842 − 599 =
32. 32.838 − 538 =
33. 33.760 − 599 =
34. 34.754 − 499 =
35. 35.422 − 197 =
36. 36.938 − 177 =
37. 37.974 − 669 =
38. 38.715 − 597 =
39. 39.738 − 299 =
40. 40.767 − 418 =

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