Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 891 · 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. 1.416 − 237 =
2. 2.949 − 618 =
3. 3.817 − 798 =
4. 4.823 − 497 =
5. 5.879 − 498 =
6. 6.796 − 498 =
7. 7.763 − 599 =
8. 8.543 − 189 =
9. 9.898 − 597 =
10. 10.619 − 399 =
11. 11.747 − 499 =
12. 12.913 − 348 =
13. 13.813 − 497 =
14. 14.952 − 299 =
15. 15.593 − 399 =
16. 16.645 − 559 =
17. 17.266 − 198 =
18. 18.255 − 187 =
19. 19.395 − 279 =
20. 20.850 − 798 =
21. 21.525 − 489 =
22. 22.819 − 798 =
23. 23.991 − 698 =
24. 24.877 − 299 =
25. 25.320 − 299 =
26. 26.613 − 537 =
27. 27.359 − 298 =
28. 28.631 − 498 =
29. 29.969 − 348 =
30. 30.696 − 599 =
31. 31.395 − 297 =
32. 32.803 − 598 =
33. 33.540 − 497 =
34. 34.934 − 279 =
35. 35.993 − 399 =
36. 36.884 − 227 =
37. 37.696 − 399 =
38. 38.586 − 338 =
39. 39.919 − 199 =
40. 40.973 − 678 =

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