Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 850 · 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. 1.717 − 298 =
2. 2.957 − 698 =
3. 3.894 − 329 =
4. 4.669 − 647 =
5. 5.885 − 798 =
6. 6.778 − 419 =
7. 7.625 − 307 =
8. 8.985 − 397 =
9. 9.784 − 599 =
10. 10.813 − 798 =
11. 11.436 − 399 =
12. 12.833 − 287 =
13. 13.843 − 198 =
14. 14.925 − 399 =
15. 15.967 − 397 =
16. 16.665 − 499 =
17. 17.821 − 239 =
18. 18.580 − 219 =
19. 19.827 − 189 =
20. 20.676 − 398 =
21. 21.640 − 607 =
22. 22.710 − 648 =
23. 23.975 − 398 =
24. 24.933 − 698 =
25. 25.969 − 297 =
26. 26.778 − 499 =
27. 27.260 − 119 =
28. 28.463 − 398 =
29. 29.943 − 299 =
30. 30.774 − 308 =
31. 31.519 − 449 =
32. 32.717 − 499 =
33. 33.845 − 498 =
34. 34.583 − 498 =
35. 35.892 − 559 =
36. 36.973 − 299 =
37. 37.484 − 399 =
38. 38.885 − 559 =
39. 39.840 − 798 =
40. 40.767 − 229 =

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