Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 61 · 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. 1.884 − 598 =
2. 2.617 − 249 =
3. 3.834 − 618 =
4. 4.894 − 648 =
5. 5.292 − 199 =
6. 6.755 − 598 =
7. 7.548 − 247 =
8. 8.778 − 698 =
9. 9.559 − 499 =
10. 10.708 − 667 =
11. 11.797 − 299 =
12. 12.917 − 458 =
13. 13.555 − 507 =
14. 14.925 − 697 =
15. 15.617 − 327 =
16. 16.768 − 499 =
17. 17.688 − 399 =
18. 18.811 − 189 =
19. 19.837 − 617 =
20. 20.855 − 597 =
21. 21.335 − 297 =
22. 22.338 − 297 =
23. 23.940 − 268 =
24. 24.999 − 698 =
25. 25.721 − 699 =
26. 26.840 − 517 =
27. 27.754 − 218 =
28. 28.773 − 468 =
29. 29.316 − 199 =
30. 30.984 − 498 =
31. 31.941 − 298 =
32. 32.970 − 798 =
33. 33.794 − 197 =
34. 34.978 − 558 =
35. 35.698 − 599 =
36. 36.495 − 328 =
37. 37.416 − 339 =
38. 38.968 − 798 =
39. 39.780 − 299 =
40. 40.979 − 298 =

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