Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 775 · 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. 1.895 − 278 =
2. 2.352 − 298 =
3. 3.525 − 139 =
4. 4.927 − 397 =
5. 5.739 − 398 =
6. 6.887 − 197 =
7. 7.613 − 598 =
8. 8.406 − 259 =
9. 9.621 − 197 =
10. 10.877 − 328 =
11. 11.851 − 798 =
12. 12.710 − 598 =
13. 13.408 − 148 =
14. 14.664 − 297 =
15. 15.436 − 379 =
16. 16.944 − 298 =
17. 17.853 − 638 =
18. 18.736 − 619 =
19. 19.627 − 498 =
20. 20.768 − 598 =
21. 21.277 − 199 =
22. 22.943 − 799 =
23. 23.670 − 327 =
24. 24.644 − 499 =
25. 25.454 − 209 =
26. 26.357 − 168 =
27. 27.781 − 587 =
28. 28.849 − 597 =
29. 29.552 − 337 =
30. 30.878 − 797 =
31. 31.910 − 597 =
32. 32.557 − 148 =
33. 33.488 − 377 =
34. 34.788 − 657 =
35. 35.763 − 598 =
36. 36.620 − 397 =
37. 37.884 − 299 =
38. 38.903 − 398 =
39. 39.814 − 118 =
40. 40.596 − 547 =

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