Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 248 · 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. 1.691 − 627 =
2. 2.932 − 799 =
3. 3.882 − 238 =
4. 4.827 − 188 =
5. 5.841 − 798 =
6. 6.985 − 279 =
7. 7.918 − 598 =
8. 8.779 − 598 =
9. 9.421 − 308 =
10. 10.809 − 498 =
11. 11.965 − 697 =
12. 12.277 − 199 =
13. 13.650 − 397 =
14. 14.895 − 437 =
15. 15.756 − 398 =
16. 16.925 − 497 =
17. 17.598 − 299 =
18. 18.794 − 398 =
19. 19.767 − 697 =
20. 20.935 − 597 =
21. 21.444 − 298 =
22. 22.747 − 297 =
23. 23.462 − 198 =
24. 24.547 − 197 =
25. 25.977 − 499 =
26. 26.754 − 419 =
27. 27.833 − 438 =
28. 28.693 − 458 =
29. 29.418 − 379 =
30. 30.744 − 598 =
31. 31.889 − 669 =
32. 32.800 − 417 =
33. 33.529 − 188 =
34. 34.970 − 599 =
35. 35.661 − 518 =
36. 36.336 − 297 =
37. 37.968 − 799 =
38. 38.784 − 397 =
39. 39.675 − 278 =
40. 40.797 − 699 =

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