Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 277 · 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. 1.922 − 297 =
2. 2.961 − 697 =
3. 3.419 − 387 =
4. 4.709 − 597 =
5. 5.443 − 298 =
6. 6.596 − 298 =
7. 7.929 − 498 =
8. 8.877 − 168 =
9. 9.614 − 308 =
10. 10.404 − 298 =
11. 11.943 − 528 =
12. 12.908 − 679 =
13. 13.586 − 129 =
14. 14.693 − 297 =
15. 15.558 − 519 =
16. 16.662 − 198 =
17. 17.759 − 597 =
18. 18.625 − 497 =
19. 19.801 − 619 =
20. 20.859 − 298 =
21. 21.769 − 697 =
22. 22.690 − 627 =
23. 23.868 − 298 =
24. 24.551 − 488 =
25. 25.546 − 199 =
26. 26.212 − 197 =
27. 27.988 − 599 =
28. 28.574 − 397 =
29. 29.791 − 377 =
30. 30.838 − 199 =
31. 31.172 − 149 =
32. 32.687 − 288 =
33. 33.508 − 469 =
34. 34.750 − 658 =
35. 35.846 − 658 =
36. 36.661 − 498 =
37. 37.439 − 277 =
38. 38.707 − 199 =
39. 39.811 − 297 =
40. 40.775 − 598 =

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