Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 177 · 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. 1.559 − 289 =
2. 2.647 − 299 =
3. 3.796 − 698 =
4. 4.988 − 528 =
5. 5.847 − 699 =
6. 6.453 − 199 =
7. 7.664 − 209 =
8. 8.918 − 598 =
9. 9.926 − 597 =
10. 10.362 − 328 =
11. 11.534 − 499 =
12. 12.636 − 397 =
13. 13.268 − 199 =
14. 14.717 − 188 =
15. 15.725 − 297 =
16. 16.466 − 298 =
17. 17.875 − 299 =
18. 18.957 − 497 =
19. 19.772 − 597 =
20. 20.711 − 418 =
21. 21.342 − 139 =
22. 22.856 − 538 =
23. 23.651 − 298 =
24. 24.999 − 697 =
25. 25.565 − 267 =
26. 26.884 − 567 =
27. 27.720 − 197 =
28. 28.450 − 389 =
29. 29.977 − 699 =
30. 30.858 − 299 =
31. 31.995 − 397 =
32. 32.830 − 499 =
33. 33.896 − 389 =
34. 34.597 − 459 =
35. 35.873 − 197 =
36. 36.855 − 619 =
37. 37.563 − 497 =
38. 38.541 − 467 =
39. 39.273 − 117 =
40. 40.929 − 387 =

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