Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 535 · 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. 1.625 − 197 =
2. 2.615 − 498 =
3. 3.423 − 387 =
4. 4.351 − 198 =
5. 5.769 − 599 =
6. 6.874 − 597 =
7. 7.936 − 497 =
8. 8.937 − 659 =
9. 9.692 − 499 =
10. 10.591 − 398 =
11. 11.363 − 297 =
12. 12.746 − 617 =
13. 13.913 − 117 =
14. 14.726 − 548 =
15. 15.889 − 298 =
16. 16.786 − 628 =
17. 17.866 − 599 =
18. 18.807 − 397 =
19. 19.902 − 798 =
20. 20.861 − 618 =
21. 21.714 − 697 =
22. 22.677 − 267 =
23. 23.943 − 397 =
24. 24.959 − 298 =
25. 25.353 − 137 =
26. 26.708 − 498 =
27. 27.692 − 658 =
28. 28.787 − 499 =
29. 29.694 − 597 =
30. 30.860 − 478 =
31. 31.937 − 598 =
32. 32.715 − 588 =
33. 33.766 − 577 =
34. 34.527 − 398 =
35. 35.940 − 698 =
36. 36.926 − 798 =
37. 37.958 − 498 =
38. 38.804 − 578 =
39. 39.576 − 447 =
40. 40.868 − 798 =

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