Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 402 · 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. 1.453 − 297 =
2. 2.853 − 298 =
3. 3.647 − 198 =
4. 4.551 − 398 =
5. 5.851 − 798 =
6. 6.797 − 297 =
7. 7.538 − 487 =
8. 8.936 − 378 =
9. 9.921 − 598 =
10. 10.779 − 299 =
11. 11.942 − 297 =
12. 12.263 − 198 =
13. 13.702 − 567 =
14. 14.893 − 799 =
15. 15.712 − 299 =
16. 16.628 − 137 =
17. 17.857 − 697 =
18. 18.483 − 298 =
19. 19.895 − 797 =
20. 20.483 − 399 =
21. 21.855 − 699 =
22. 22.983 − 799 =
23. 23.675 − 658 =
24. 24.948 − 598 =
25. 25.876 − 597 =
26. 26.942 − 597 =
27. 27.704 − 279 =
28. 28.417 − 397 =
29. 29.743 − 639 =
30. 30.926 − 249 =
31. 31.732 − 228 =
32. 32.799 − 349 =
33. 33.858 − 598 =
34. 34.534 − 199 =
35. 35.841 − 797 =
36. 36.448 − 387 =
37. 37.756 − 199 =
38. 38.455 − 248 =
39. 39.937 − 558 =
40. 40.440 − 248 =

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