Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 259 · 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. 1.586 − 297 =
2. 2.901 − 489 =
3. 3.736 − 609 =
4. 4.600 − 519 =
5. 5.410 − 357 =
6. 6.519 − 497 =
7. 7.549 − 438 =
8. 8.332 − 298 =
9. 9.351 − 218 =
10. 10.799 − 527 =
11. 11.949 − 799 =
12. 12.624 − 597 =
13. 13.769 − 689 =
14. 14.683 − 348 =
15. 15.887 − 389 =
16. 16.654 − 297 =
17. 17.466 − 248 =
18. 18.791 − 479 =
19. 19.970 − 208 =
20. 20.741 − 398 =
21. 21.496 − 397 =
22. 22.694 − 198 =
23. 23.891 − 638 =
24. 24.732 − 599 =
25. 25.922 − 309 =
26. 26.464 − 137 =
27. 27.672 − 198 =
28. 28.962 − 477 =
29. 29.279 − 157 =
30. 30.906 − 797 =
31. 31.462 − 197 =
32. 32.788 − 589 =
33. 33.817 − 799 =
34. 34.989 − 477 =
35. 35.581 − 198 =
36. 36.871 − 797 =
37. 37.927 − 358 =
38. 38.880 − 618 =
39. 39.364 − 198 =
40. 40.172 − 158 =

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