Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 350 · 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. 1.998 − 589 =
2. 2.860 − 688 =
3. 3.823 − 599 =
4. 4.813 − 797 =
5. 5.548 − 498 =
6. 6.671 − 587 =
7. 7.763 − 419 =
8. 8.765 − 378 =
9. 9.824 − 698 =
10. 10.854 − 699 =
11. 11.842 − 529 =
12. 12.897 − 639 =
13. 13.257 − 167 =
14. 14.574 − 379 =
15. 15.405 − 207 =
16. 16.782 − 248 =
17. 17.938 − 689 =
18. 18.715 − 699 =
19. 19.931 − 197 =
20. 20.915 − 677 =
21. 21.926 − 559 =
22. 22.834 − 698 =
23. 23.464 − 299 =
24. 24.918 − 499 =
25. 25.736 − 639 =
26. 26.932 − 299 =
27. 27.809 − 459 =
28. 28.941 − 798 =
29. 29.909 − 608 =
30. 30.861 − 798 =
31. 31.728 − 199 =
32. 32.438 − 397 =
33. 33.822 − 697 =
34. 34.987 − 497 =
35. 35.810 − 158 =
36. 36.610 − 499 =
37. 37.718 − 329 =
38. 38.975 − 119 =
39. 39.825 − 798 =
40. 40.225 − 198 =

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