Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 167 · 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. 1.946 − 627 =
2. 2.360 − 338 =
3. 3.898 − 599 =
4. 4.494 − 298 =
5. 5.763 − 497 =
6. 6.912 − 199 =
7. 7.943 − 599 =
8. 8.764 − 567 =
9. 9.990 − 799 =
10. 10.735 − 697 =
11. 11.909 − 329 =
12. 12.492 − 299 =
13. 13.863 − 499 =
14. 14.853 − 697 =
15. 15.844 − 358 =
16. 16.882 − 358 =
17. 17.617 − 147 =
18. 18.239 − 197 =
19. 19.656 − 598 =
20. 20.944 − 799 =
21. 21.250 − 188 =
22. 22.565 − 399 =
23. 23.688 − 557 =
24. 24.902 − 698 =
25. 25.929 − 497 =
26. 26.995 − 659 =
27. 27.958 − 298 =
28. 28.744 − 697 =
29. 29.853 − 489 =
30. 30.925 − 689 =
31. 31.476 − 359 =
32. 32.750 − 697 =
33. 33.478 − 337 =
34. 34.731 − 157 =
35. 35.769 − 599 =
36. 36.657 − 198 =
37. 37.927 − 499 =
38. 38.726 − 417 =
39. 39.919 − 499 =
40. 40.936 − 197 =

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