Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 807 · 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. 1.686 − 557 =
2. 2.265 − 167 =
3. 3.989 − 497 =
4. 4.593 − 297 =
5. 5.203 − 187 =
6. 6.382 − 128 =
7. 7.328 − 147 =
8. 8.778 − 667 =
9. 9.322 − 297 =
10. 10.303 − 208 =
11. 11.583 − 227 =
12. 12.970 − 467 =
13. 13.833 − 619 =
14. 14.876 − 499 =
15. 15.520 − 499 =
16. 16.286 − 249 =
17. 17.948 − 659 =
18. 18.397 − 308 =
19. 19.714 − 199 =
20. 20.843 − 307 =
21. 21.953 − 597 =
22. 22.893 − 699 =
23. 23.502 − 329 =
24. 24.422 − 197 =
25. 25.963 − 397 =
26. 26.965 − 188 =
27. 27.632 − 558 =
28. 28.630 − 199 =
29. 29.882 − 687 =
30. 30.544 − 139 =
31. 31.744 − 187 =
32. 32.858 − 498 =
33. 33.866 − 187 =
34. 34.291 − 199 =
35. 35.954 − 308 =
36. 36.871 − 297 =
37. 37.898 − 398 =
38. 38.734 − 697 =
39. 39.442 − 399 =
40. 40.750 − 199 =

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