Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 463 · 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. 1.928 − 688 =
2. 2.713 − 379 =
3. 3.748 − 398 =
4. 4.693 − 597 =
5. 5.789 − 319 =
6. 6.740 − 599 =
7. 7.782 − 558 =
8. 8.218 − 199 =
9. 9.956 − 598 =
10. 10.726 − 638 =
11. 11.461 − 409 =
12. 12.904 − 699 =
13. 13.901 − 797 =
14. 14.698 − 278 =
15. 15.972 − 798 =
16. 16.877 − 698 =
17. 17.898 − 549 =
18. 18.846 − 199 =
19. 19.835 − 677 =
20. 20.641 − 599 =
21. 21.828 − 797 =
22. 22.299 − 258 =
23. 23.904 − 698 =
24. 24.569 − 439 =
25. 25.920 − 459 =
26. 26.875 − 687 =
27. 27.477 − 397 =
28. 28.912 − 298 =
29. 29.194 − 179 =
30. 30.793 − 639 =
31. 31.952 − 249 =
32. 32.699 − 498 =
33. 33.832 − 698 =
34. 34.253 − 148 =
35. 35.688 − 117 =
36. 36.540 − 497 =
37. 37.829 − 197 =
38. 38.564 − 208 =
39. 39.676 − 658 =
40. 40.834 − 698 =

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