Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 676 · 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. 1.654 − 269 =
2. 2.625 − 388 =
3. 3.947 − 568 =
4. 4.768 − 699 =
5. 5.713 − 698 =
6. 6.936 − 357 =
7. 7.857 − 297 =
8. 8.468 − 399 =
9. 9.636 − 607 =
10. 10.939 − 589 =
11. 11.687 − 198 =
12. 12.817 − 698 =
13. 13.742 − 559 =
14. 14.821 − 699 =
15. 15.912 − 597 =
16. 16.809 − 498 =
17. 17.704 − 347 =
18. 18.684 − 628 =
19. 19.499 − 399 =
20. 20.657 − 599 =
21. 21.681 − 409 =
22. 22.739 − 628 =
23. 23.969 − 648 =
24. 24.404 − 198 =
25. 25.771 − 599 =
26. 26.945 − 198 =
27. 27.894 − 569 =
28. 28.957 − 129 =
29. 29.946 − 797 =
30. 30.678 − 297 =
31. 31.443 − 347 =
32. 32.995 − 599 =
33. 33.919 − 199 =
34. 34.858 − 299 =
35. 35.992 − 397 =
36. 36.852 − 499 =
37. 37.461 − 198 =
38. 38.521 − 329 =
39. 39.907 − 208 =
40. 40.737 − 537 =

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