Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 713 · 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. 1.480 − 137 =
2. 2.241 − 198 =
3. 3.523 − 288 =
4. 4.927 − 398 =
5. 5.776 − 339 =
6. 6.795 − 699 =
7. 7.939 − 799 =
8. 8.559 − 119 =
9. 9.479 − 299 =
10. 10.937 − 398 =
11. 11.708 − 289 =
12. 12.828 − 699 =
13. 13.604 − 299 =
14. 14.735 − 698 =
15. 15.540 − 499 =
16. 16.771 − 498 =
17. 17.795 − 457 =
18. 18.756 − 597 =
19. 19.663 − 498 =
20. 20.618 − 259 =
21. 21.849 − 798 =
22. 22.556 − 139 =
23. 23.697 − 537 =
24. 24.838 − 497 =
25. 25.455 − 298 =
26. 26.801 − 498 =
27. 27.877 − 657 =
28. 28.667 − 497 =
29. 29.944 − 798 =
30. 30.847 − 799 =
31. 31.786 − 499 =
32. 32.795 − 298 =
33. 33.935 − 687 =
34. 34.912 − 597 =
35. 35.919 − 797 =
36. 36.964 − 597 =
37. 37.753 − 459 =
38. 38.834 − 197 =
39. 39.636 − 497 =
40. 40.669 − 369 =

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