Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 639 · 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. 1.850 − 328 =
2. 2.577 − 439 =
3. 3.633 − 198 =
4. 4.451 − 298 =
5. 5.878 − 399 =
6. 6.820 − 597 =
7. 7.864 − 197 =
8. 8.712 − 597 =
9. 9.884 − 798 =
10. 10.825 − 179 =
11. 11.943 − 218 =
12. 12.841 − 797 =
13. 13.736 − 698 =
14. 14.504 − 299 =
15. 15.452 − 299 =
16. 16.892 − 539 =
17. 17.795 − 198 =
18. 18.914 − 398 =
19. 19.503 − 398 =
20. 20.488 − 297 =
21. 21.448 − 197 =
22. 22.957 − 397 =
23. 23.224 − 199 =
24. 24.972 − 119 =
25. 25.838 − 799 =
26. 26.426 − 298 =
27. 27.652 − 599 =
28. 28.404 − 277 =
29. 29.641 − 397 =
30. 30.929 − 139 =
31. 31.580 − 337 =
32. 32.930 − 497 =
33. 33.988 − 699 =
34. 34.881 − 299 =
35. 35.898 − 799 =
36. 36.815 − 198 =
37. 37.827 − 279 =
38. 38.881 − 599 =
39. 39.411 − 218 =
40. 40.332 − 197 =

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