Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 292 · 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. 1.862 − 457 =
2. 2.599 − 297 =
3. 3.562 − 299 =
4. 4.930 − 478 =
5. 5.520 − 398 =
6. 6.712 − 199 =
7. 7.480 − 299 =
8. 8.793 − 357 =
9. 9.810 − 197 =
10. 10.926 − 197 =
11. 11.613 − 497 =
12. 12.891 − 438 =
13. 13.809 − 597 =
14. 14.767 − 198 =
15. 15.762 − 148 =
16. 16.880 − 797 =
17. 17.675 − 149 =
18. 18.644 − 298 =
19. 19.914 − 279 =
20. 20.904 − 637 =
21. 21.611 − 227 =
22. 22.610 − 397 =
23. 23.540 − 278 =
24. 24.431 − 209 =
25. 25.653 − 228 =
26. 26.648 − 179 =
27. 27.605 − 298 =
28. 28.323 − 229 =
29. 29.828 − 199 =
30. 30.656 − 298 =
31. 31.965 − 599 =
32. 32.759 − 699 =
33. 33.232 − 129 =
34. 34.970 − 687 =
35. 35.883 − 598 =
36. 36.539 − 499 =
37. 37.246 − 199 =
38. 38.826 − 428 =
39. 39.605 − 319 =
40. 40.913 − 597 =

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