Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 172 · 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. 1.846 − 199 =
2. 2.551 − 478 =
3. 3.964 − 799 =
4. 4.523 − 279 =
5. 5.574 − 498 =
6. 6.765 − 269 =
7. 7.916 − 599 =
8. 8.958 − 648 =
9. 9.447 − 398 =
10. 10.636 − 469 =
11. 11.993 − 197 =
12. 12.611 − 499 =
13. 13.858 − 549 =
14. 14.845 − 528 =
15. 15.908 − 697 =
16. 16.578 − 497 =
17. 17.721 − 598 =
18. 18.416 − 398 =
19. 19.987 − 197 =
20. 20.918 − 699 =
21. 21.738 − 699 =
22. 22.663 − 197 =
23. 23.705 − 599 =
24. 24.412 − 399 =
25. 25.833 − 598 =
26. 26.548 − 209 =
27. 27.790 − 559 =
28. 28.650 − 577 =
29. 29.469 − 399 =
30. 30.719 − 397 =
31. 31.469 − 199 =
32. 32.756 − 629 =
33. 33.713 − 197 =
34. 34.655 − 397 =
35. 35.636 − 497 =
36. 36.550 − 499 =
37. 37.982 − 498 =
38. 38.722 − 279 =
39. 39.954 − 798 =
40. 40.252 − 217 =

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