Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 984 · 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. 1.799 − 199 =
2. 2.536 − 227 =
3. 3.588 − 199 =
4. 4.750 − 437 =
5. 5.337 − 197 =
6. 6.773 − 298 =
7. 7.572 − 498 =
8. 8.690 − 499 =
9. 9.470 − 298 =
10. 10.925 − 599 =
11. 11.813 − 179 =
12. 12.431 − 149 =
13. 13.692 − 497 =
14. 14.342 − 218 =
15. 15.897 − 797 =
16. 16.553 − 237 =
17. 17.916 − 209 =
18. 18.907 − 499 =
19. 19.918 − 577 =
20. 20.749 − 198 =
21. 21.560 − 399 =
22. 22.614 − 199 =
23. 23.576 − 359 =
24. 24.781 − 698 =
25. 25.759 − 568 =
26. 26.752 − 609 =
27. 27.344 − 328 =
28. 28.867 − 508 =
29. 29.814 − 799 =
30. 30.389 − 267 =
31. 31.812 − 599 =
32. 32.745 − 499 =
33. 33.667 − 598 =
34. 34.848 − 797 =
35. 35.602 − 238 =
36. 36.670 − 397 =
37. 37.776 − 398 =
38. 38.487 − 269 =
39. 39.922 − 598 =
40. 40.772 − 399 =

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