Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 534 · 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. 1.372 − 287 =
2. 2.708 − 668 =
3. 3.809 − 657 =
4. 4.741 − 157 =
5. 5.776 − 698 =
6. 6.956 − 439 =
7. 7.970 − 398 =
8. 8.779 − 599 =
9. 9.724 − 698 =
10. 10.978 − 598 =
11. 11.960 − 668 =
12. 12.640 − 579 =
13. 13.938 − 699 =
14. 14.550 − 137 =
15. 15.673 − 649 =
16. 16.993 − 677 =
17. 17.523 − 499 =
18. 18.726 − 657 =
19. 19.843 − 299 =
20. 20.876 − 498 =
21. 21.851 − 667 =
22. 22.774 − 399 =
23. 23.816 − 699 =
24. 24.613 − 399 =
25. 25.509 − 399 =
26. 26.681 − 597 =
27. 27.526 − 199 =
28. 28.985 − 499 =
29. 29.961 − 388 =
30. 30.904 − 597 =
31. 31.778 − 198 =
32. 32.803 − 687 =
33. 33.854 − 539 =
34. 34.397 − 159 =
35. 35.832 − 497 =
36. 36.752 − 278 =
37. 37.974 − 797 =
38. 38.709 − 498 =
39. 39.349 − 199 =
40. 40.944 − 797 =

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