Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 722 · 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. 1.995 − 327 =
2. 2.320 − 198 =
3. 3.625 − 589 =
4. 4.663 − 399 =
5. 5.942 − 499 =
6. 6.771 − 297 =
7. 7.786 − 497 =
8. 8.700 − 297 =
9. 9.427 − 398 =
10. 10.537 − 268 =
11. 11.939 − 697 =
12. 12.962 − 597 =
13. 13.902 − 298 =
14. 14.724 − 117 =
15. 15.664 − 358 =
16. 16.769 − 688 =
17. 17.437 − 397 =
18. 18.563 − 198 =
19. 19.713 − 199 =
20. 20.791 − 298 =
21. 21.662 − 478 =
22. 22.277 − 147 =
23. 23.544 − 398 =
24. 24.956 − 598 =
25. 25.371 − 138 =
26. 26.845 − 598 =
27. 27.822 − 147 =
28. 28.889 − 299 =
29. 29.604 − 497 =
30. 30.544 − 399 =
31. 31.705 − 199 =
32. 32.825 − 799 =
33. 33.919 − 609 =
34. 34.703 − 647 =
35. 35.731 − 687 =
36. 36.477 − 297 =
37. 37.444 − 428 =
38. 38.762 − 128 =
39. 39.798 − 599 =
40. 40.815 − 698 =

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