Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 627 · 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. 1.968 − 618 =
2. 2.657 − 437 =
3. 3.654 − 267 =
4. 4.655 − 138 =
5. 5.482 − 199 =
6. 6.693 − 297 =
7. 7.671 − 599 =
8. 8.718 − 689 =
9. 9.779 − 509 =
10. 10.541 − 418 =
11. 11.315 − 199 =
12. 12.677 − 498 =
13. 13.800 − 598 =
14. 14.832 − 499 =
15. 15.630 − 209 =
16. 16.524 − 498 =
17. 17.785 − 599 =
18. 18.564 − 189 =
19. 19.904 − 608 =
20. 20.854 − 398 =
21. 21.747 − 477 =
22. 22.650 − 208 =
23. 23.879 − 147 =
24. 24.353 − 227 =
25. 25.955 − 497 =
26. 26.913 − 398 =
27. 27.283 − 198 =
28. 28.882 − 689 =
29. 29.722 − 499 =
30. 30.284 − 198 =
31. 31.606 − 209 =
32. 32.480 − 427 =
33. 33.844 − 797 =
34. 34.541 − 447 =
35. 35.590 − 299 =
36. 36.774 − 628 =
37. 37.827 − 598 =
38. 38.404 − 387 =
39. 39.572 − 197 =
40. 40.626 − 497 =

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