Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 263 · 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. 1.908 − 338 =
2. 2.886 − 447 =
3. 3.726 − 377 =
4. 4.534 − 297 =
5. 5.423 − 398 =
6. 6.861 − 799 =
7. 7.750 − 688 =
8. 8.880 − 657 =
9. 9.940 − 597 =
10. 10.959 − 598 =
11. 11.808 − 597 =
12. 12.915 − 698 =
13. 13.353 − 197 =
14. 14.945 − 797 =
15. 15.860 − 397 =
16. 16.563 − 399 =
17. 17.431 − 239 =
18. 18.877 − 799 =
19. 19.787 − 498 =
20. 20.826 − 697 =
21. 21.946 − 197 =
22. 22.534 − 379 =
23. 23.614 − 599 =
24. 24.976 − 798 =
25. 25.977 − 299 =
26. 26.520 − 419 =
27. 27.938 − 149 =
28. 28.755 − 387 =
29. 29.995 − 579 =
30. 30.888 − 327 =
31. 31.710 − 117 =
32. 32.669 − 297 =
33. 33.522 − 379 =
34. 34.747 − 147 =
35. 35.776 − 697 =
36. 36.617 − 297 =
37. 37.649 − 499 =
38. 38.863 − 799 =
39. 39.660 − 399 =
40. 40.969 − 178 =

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