Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 127 · 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. 1.769 − 459 =
2. 2.144 − 119 =
3. 3.986 − 599 =
4. 4.560 − 157 =
5. 5.712 − 497 =
6. 6.657 − 427 =
7. 7.962 − 797 =
8. 8.750 − 697 =
9. 9.988 − 119 =
10. 10.677 − 599 =
11. 11.736 − 397 =
12. 12.460 − 298 =
13. 13.852 − 299 =
14. 14.911 − 497 =
15. 15.982 − 798 =
16. 16.658 − 169 =
17. 17.735 − 329 =
18. 18.921 − 518 =
19. 19.657 − 597 =
20. 20.820 − 298 =
21. 21.523 − 297 =
22. 22.755 − 198 =
23. 23.721 − 699 =
24. 24.759 − 409 =
25. 25.504 − 377 =
26. 26.734 − 297 =
27. 27.941 − 797 =
28. 28.704 − 659 =
29. 29.927 − 199 =
30. 30.788 − 249 =
31. 31.776 − 599 =
32. 32.776 − 197 =
33. 33.601 − 489 =
34. 34.816 − 698 =
35. 35.531 − 397 =
36. 36.609 − 298 =
37. 37.792 − 678 =
38. 38.641 − 297 =
39. 39.981 − 569 =
40. 40.990 − 499 =

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