Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 932 · 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. 1.684 − 197 =
2. 2.906 − 199 =
3. 3.773 − 698 =
4. 4.747 − 398 =
5. 5.515 − 229 =
6. 6.887 − 687 =
7. 7.726 − 399 =
8. 8.667 − 198 =
9. 9.708 − 227 =
10. 10.275 − 197 =
11. 11.608 − 389 =
12. 12.491 − 277 =
13. 13.949 − 698 =
14. 14.943 − 577 =
15. 15.433 − 199 =
16. 16.535 − 368 =
17. 17.742 − 297 =
18. 18.378 − 297 =
19. 19.773 − 417 =
20. 20.813 − 697 =
21. 21.782 − 477 =
22. 22.907 − 598 =
23. 23.855 − 799 =
24. 24.886 − 299 =
25. 25.907 − 597 =
26. 26.965 − 349 =
27. 27.641 − 538 =
28. 28.770 − 698 =
29. 29.686 − 338 =
30. 30.379 − 197 =
31. 31.865 − 598 =
32. 32.964 − 699 =
33. 33.715 − 647 =
34. 34.850 − 297 =
35. 35.625 − 457 =
36. 36.630 − 499 =
37. 37.737 − 167 =
38. 38.803 − 247 =
39. 39.886 − 199 =
40. 40.585 − 297 =

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