Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 709 · 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. 1.957 − 797 =
2. 2.933 − 419 =
3. 3.740 − 599 =
4. 4.463 − 179 =
5. 5.665 − 398 =
6. 6.385 − 199 =
7. 7.683 − 217 =
8. 8.635 − 197 =
9. 9.839 − 298 =
10. 10.848 − 799 =
11. 11.943 − 698 =
12. 12.750 − 199 =
13. 13.918 − 799 =
14. 14.857 − 348 =
15. 15.976 − 548 =
16. 16.983 − 797 =
17. 17.551 − 418 =
18. 18.300 − 179 =
19. 19.877 − 499 =
20. 20.830 − 269 =
21. 21.382 − 318 =
22. 22.314 − 127 =
23. 23.845 − 368 =
24. 24.785 − 298 =
25. 25.583 − 198 =
26. 26.962 − 699 =
27. 27.881 − 597 =
28. 28.869 − 197 =
29. 29.958 − 699 =
30. 30.678 − 459 =
31. 31.745 − 599 =
32. 32.549 − 327 =
33. 33.490 − 439 =
34. 34.484 − 287 =
35. 35.926 − 268 =
36. 36.881 − 599 =
37. 37.995 − 207 =
38. 38.789 − 357 =
39. 39.917 − 699 =
40. 40.542 − 359 =

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