Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 799 · 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. 1.966 − 277 =
2. 2.928 − 699 =
3. 3.915 − 698 =
4. 4.717 − 598 =
5. 5.756 − 698 =
6. 6.921 − 697 =
7. 7.364 − 279 =
8. 8.897 − 698 =
9. 9.766 − 497 =
10. 10.875 − 799 =
11. 11.878 − 598 =
12. 12.950 − 647 =
13. 13.709 − 398 =
14. 14.905 − 298 =
15. 15.881 − 398 =
16. 16.893 − 698 =
17. 17.792 − 599 =
18. 18.829 − 799 =
19. 19.871 − 799 =
20. 20.579 − 547 =
21. 21.383 − 158 =
22. 22.971 − 599 =
23. 23.675 − 398 =
24. 24.838 − 699 =
25. 25.560 − 198 =
26. 26.892 − 697 =
27. 27.293 − 227 =
28. 28.808 − 128 =
29. 29.377 − 297 =
30. 30.692 − 498 =
31. 31.711 − 289 =
32. 32.879 − 698 =
33. 33.694 − 569 =
34. 34.637 − 199 =
35. 35.971 − 337 =
36. 36.712 − 678 =
37. 37.878 − 798 =
38. 38.790 − 439 =
39. 39.651 − 297 =
40. 40.747 − 397 =

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