Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 466 · 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. 1.367 − 297 =
2. 2.909 − 699 =
3. 3.270 − 199 =
4. 4.785 − 398 =
5. 5.743 − 588 =
6. 6.505 − 299 =
7. 7.922 − 799 =
8. 8.984 − 339 =
9. 9.703 − 398 =
10. 10.566 − 308 =
11. 11.590 − 497 =
12. 12.662 − 568 =
13. 13.932 − 629 =
14. 14.672 − 567 =
15. 15.820 − 298 =
16. 16.398 − 337 =
17. 17.803 − 127 =
18. 18.594 − 419 =
19. 19.681 − 599 =
20. 20.807 − 297 =
21. 21.494 − 299 =
22. 22.769 − 559 =
23. 23.982 − 357 =
24. 24.646 − 299 =
25. 25.982 − 197 =
26. 26.329 − 297 =
27. 27.877 − 598 =
28. 28.605 − 577 =
29. 29.600 − 198 =
30. 30.703 − 597 =
31. 31.482 − 397 =
32. 32.597 − 499 =
33. 33.999 − 698 =
34. 34.918 − 698 =
35. 35.456 − 377 =
36. 36.637 − 499 =
37. 37.705 − 258 =
38. 38.884 − 597 =
39. 39.737 − 197 =
40. 40.766 − 399 =

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