Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 252 · 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. 1.762 − 697 =
2. 2.424 − 298 =
3. 3.795 − 497 =
4. 4.852 − 349 =
5. 5.585 − 398 =
6. 6.796 − 199 =
7. 7.895 − 179 =
8. 8.832 − 558 =
9. 9.774 − 597 =
10. 10.721 − 599 =
11. 11.956 − 128 =
12. 12.863 − 688 =
13. 13.807 − 697 =
14. 14.675 − 569 =
15. 15.577 − 398 =
16. 16.496 − 358 =
17. 17.703 − 497 =
18. 18.875 − 528 =
19. 19.643 − 297 =
20. 20.454 − 298 =
21. 21.978 − 699 =
22. 22.953 − 797 =
23. 23.633 − 599 =
24. 24.932 − 299 =
25. 25.777 − 599 =
26. 26.231 − 199 =
27. 27.747 − 677 =
28. 28.788 − 457 =
29. 29.870 − 148 =
30. 30.827 − 548 =
31. 31.994 − 377 =
32. 32.925 − 398 =
33. 33.582 − 288 =
34. 34.243 − 199 =
35. 35.756 − 197 =
36. 36.679 − 598 =
37. 37.812 − 797 =
38. 38.574 − 498 =
39. 39.862 − 527 =
40. 40.967 − 198 =

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