Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 539 · 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. 1.763 − 228 =
2. 2.746 − 499 =
3. 3.950 − 599 =
4. 4.435 − 297 =
5. 5.848 − 499 =
6. 6.724 − 637 =
7. 7.427 − 307 =
8. 8.880 − 629 =
9. 9.867 − 399 =
10. 10.590 − 267 =
11. 11.327 − 288 =
12. 12.561 − 297 =
13. 13.693 − 678 =
14. 14.988 − 697 =
15. 15.737 − 499 =
16. 16.428 − 188 =
17. 17.511 − 298 =
18. 18.994 − 499 =
19. 19.539 − 198 =
20. 20.672 − 387 =
21. 21.594 − 399 =
22. 22.606 − 499 =
23. 23.795 − 598 =
24. 24.842 − 799 =
25. 25.476 − 397 =
26. 26.892 − 608 =
27. 27.598 − 397 =
28. 28.737 − 667 =
29. 29.591 − 298 =
30. 30.699 − 597 =
31. 31.903 − 697 =
32. 32.939 − 627 =
33. 33.248 − 197 =
34. 34.897 − 299 =
35. 35.262 − 189 =
36. 36.672 − 598 =
37. 37.959 − 699 =
38. 38.805 − 648 =
39. 39.767 − 298 =
40. 40.531 − 299 =

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