Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 493 · 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. 1.688 − 567 =
2. 2.684 − 397 =
3. 3.673 − 597 =
4. 4.430 − 218 =
5. 5.831 − 597 =
6. 6.690 − 498 =
7. 7.619 − 599 =
8. 8.913 − 587 =
9. 9.656 − 598 =
10. 10.900 − 459 =
11. 11.977 − 799 =
12. 12.892 − 798 =
13. 13.949 − 598 =
14. 14.760 − 497 =
15. 15.559 − 429 =
16. 16.867 − 689 =
17. 17.558 − 498 =
18. 18.656 − 218 =
19. 19.617 − 447 =
20. 20.990 − 698 =
21. 21.318 − 199 =
22. 22.646 − 548 =
23. 23.923 − 597 =
24. 24.279 − 199 =
25. 25.758 − 698 =
26. 26.936 − 798 =
27. 27.998 − 638 =
28. 28.767 − 698 =
29. 29.434 − 398 =
30. 30.448 − 388 =
31. 31.666 − 497 =
32. 32.835 − 598 =
33. 33.542 − 398 =
34. 34.573 − 397 =
35. 35.559 − 197 =
36. 36.386 − 288 =
37. 37.510 − 457 =
38. 38.873 − 597 =
39. 39.832 − 799 =
40. 40.295 − 199 =

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