Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 542 · 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. 1.927 − 567 =
2. 2.834 − 297 =
3. 3.912 − 399 =
4. 4.854 − 597 =
5. 5.549 − 297 =
6. 6.747 − 687 =
7. 7.857 − 499 =
8. 8.537 − 508 =
9. 9.988 − 799 =
10. 10.745 − 588 =
11. 11.689 − 199 =
12. 12.817 − 299 =
13. 13.513 − 299 =
14. 14.821 − 798 =
15. 15.662 − 237 =
16. 16.937 − 697 =
17. 17.416 − 397 =
18. 18.860 − 469 =
19. 19.293 − 198 =
20. 20.631 − 598 =
21. 21.635 − 599 =
22. 22.521 − 348 =
23. 23.709 − 167 =
24. 24.645 − 499 =
25. 25.451 − 198 =
26. 26.839 − 698 =
27. 27.911 − 228 =
28. 28.999 − 599 =
29. 29.400 − 299 =
30. 30.503 − 199 =
31. 31.533 − 399 =
32. 32.893 − 599 =
33. 33.805 − 197 =
34. 34.994 − 299 =
35. 35.560 − 178 =
36. 36.852 − 219 =
37. 37.435 − 288 =
38. 38.723 − 599 =
39. 39.630 − 239 =
40. 40.609 − 428 =

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