Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 409 · 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. 1.979 − 699 =
2. 2.846 − 399 =
3. 3.511 − 299 =
4. 4.853 − 467 =
5. 5.995 − 698 =
6. 6.699 − 298 =
7. 7.953 − 298 =
8. 8.916 − 669 =
9. 9.963 − 698 =
10. 10.693 − 657 =
11. 11.864 − 799 =
12. 12.714 − 598 =
13. 13.537 − 298 =
14. 14.986 − 199 =
15. 15.514 − 499 =
16. 16.885 − 697 =
17. 17.955 − 797 =
18. 18.616 − 397 =
19. 19.888 − 797 =
20. 20.987 − 618 =
21. 21.723 − 197 =
22. 22.887 − 599 =
23. 23.919 − 659 =
24. 24.668 − 598 =
25. 25.682 − 298 =
26. 26.834 − 657 =
27. 27.867 − 698 =
28. 28.797 − 287 =
29. 29.733 − 459 =
30. 30.504 − 298 =
31. 31.845 − 798 =
32. 32.817 − 399 =
33. 33.953 − 678 =
34. 34.969 − 797 =
35. 35.554 − 257 =
36. 36.904 − 297 =
37. 37.913 − 277 =
38. 38.886 − 598 =
39. 39.282 − 198 =
40. 40.839 − 447 =

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