Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 905 · 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. 1.649 − 197 =
2. 2.494 − 387 =
3. 3.816 − 197 =
4. 4.823 − 798 =
5. 5.761 − 499 =
6. 6.683 − 598 =
7. 7.941 − 628 =
8. 8.534 − 299 =
9. 9.729 − 499 =
10. 10.493 − 327 =
11. 11.685 − 197 =
12. 12.786 − 699 =
13. 13.719 − 597 =
14. 14.646 − 199 =
15. 15.934 − 677 =
16. 16.886 − 297 =
17. 17.689 − 499 =
18. 18.445 − 297 =
19. 19.920 − 799 =
20. 20.220 − 198 =
21. 21.831 − 697 =
22. 22.936 − 498 =
23. 23.856 − 198 =
24. 24.743 − 409 =
25. 25.594 − 197 =
26. 26.839 − 397 =
27. 27.871 − 339 =
28. 28.950 − 698 =
29. 29.832 − 698 =
30. 30.584 − 559 =
31. 31.768 − 269 =
32. 32.972 − 257 =
33. 33.996 − 799 =
34. 34.990 − 688 =
35. 35.845 − 698 =
36. 36.694 − 199 =
37. 37.498 − 298 =
38. 38.384 − 308 =
39. 39.839 − 527 =
40. 40.884 − 799 =

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