Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 943 · 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. 1.647 − 259 =
2. 2.250 − 197 =
3. 3.784 − 497 =
4. 4.908 − 538 =
5. 5.509 − 298 =
6. 6.906 − 427 =
7. 7.543 − 497 =
8. 8.775 − 387 =
9. 9.922 − 699 =
10. 10.794 − 298 =
11. 11.494 − 299 =
12. 12.624 − 387 =
13. 13.820 − 598 =
14. 14.626 − 499 =
15. 15.984 − 797 =
16. 16.824 − 697 =
17. 17.807 − 639 =
18. 18.649 − 199 =
19. 19.857 − 467 =
20. 20.790 − 397 =
21. 21.605 − 129 =
22. 22.942 − 468 =
23. 23.891 − 599 =
24. 24.711 − 637 =
25. 25.833 − 598 =
26. 26.310 − 198 =
27. 27.772 − 518 =
28. 28.705 − 327 =
29. 29.697 − 298 =
30. 30.907 − 417 =
31. 31.762 − 538 =
32. 32.746 − 698 =
33. 33.731 − 198 =
34. 34.627 − 497 =
35. 35.925 − 699 =
36. 36.785 − 608 =
37. 37.893 − 668 =
38. 38.625 − 599 =
39. 39.908 − 798 =
40. 40.976 − 699 =

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