Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 426 · 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. 1.562 − 499 =
2. 2.652 − 397 =
3. 3.755 − 598 =
4. 4.784 − 138 =
5. 5.379 − 138 =
6. 6.704 − 657 =
7. 7.933 − 298 =
8. 8.322 − 248 =
9. 9.802 − 199 =
10. 10.445 − 259 =
11. 11.347 − 267 =
12. 12.941 − 597 =
13. 13.837 − 797 =
14. 14.671 − 357 =
15. 15.464 − 197 =
16. 16.661 − 598 =
17. 17.577 − 547 =
18. 18.841 − 597 =
19. 19.659 − 399 =
20. 20.873 − 798 =
21. 21.343 − 199 =
22. 22.740 − 598 =
23. 23.460 − 238 =
24. 24.869 − 699 =
25. 25.696 − 559 =
26. 26.838 − 299 =
27. 27.770 − 429 =
28. 28.465 − 399 =
29. 29.861 − 137 =
30. 30.829 − 497 =
31. 31.958 − 697 =
32. 32.455 − 388 =
33. 33.873 − 799 =
34. 34.852 − 599 =
35. 35.877 − 699 =
36. 36.747 − 378 =
37. 37.808 − 558 =
38. 38.794 − 697 =
39. 39.795 − 318 =
40. 40.852 − 299 =

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