Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 819 · 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. 1.712 − 597 =
2. 2.582 − 499 =
3. 3.787 − 158 =
4. 4.213 − 198 =
5. 5.944 − 498 =
6. 6.700 − 597 =
7. 7.794 − 699 =
8. 8.562 − 509 =
9. 9.728 − 509 =
10. 10.766 − 229 =
11. 11.947 − 229 =
12. 12.863 − 697 =
13. 13.815 − 299 =
14. 14.925 − 668 =
15. 15.671 − 399 =
16. 16.554 − 519 =
17. 17.428 − 327 =
18. 18.734 − 179 =
19. 19.626 − 498 =
20. 20.866 − 269 =
21. 21.868 − 698 =
22. 22.830 − 537 =
23. 23.783 − 609 =
24. 24.636 − 498 =
25. 25.635 − 418 =
26. 26.754 − 669 =
27. 27.664 − 497 =
28. 28.820 − 537 =
29. 29.671 − 499 =
30. 30.749 − 327 =
31. 31.908 − 657 =
32. 32.556 − 157 =
33. 33.711 − 199 =
34. 34.371 − 198 =
35. 35.535 − 447 =
36. 36.471 − 297 =
37. 37.644 − 297 =
38. 38.976 − 799 =
39. 39.934 − 397 =
40. 40.583 − 377 =

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