Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 428 · 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. 1.892 − 539 =
2. 2.972 − 198 =
3. 3.918 − 599 =
4. 4.808 − 199 =
5. 5.546 − 199 =
6. 6.402 − 289 =
7. 7.836 − 597 =
8. 8.819 − 699 =
9. 9.931 − 198 =
10. 10.524 − 497 =
11. 11.943 − 119 =
12. 12.993 − 699 =
13. 13.697 − 658 =
14. 14.962 − 459 =
15. 15.874 − 599 =
16. 16.594 − 308 =
17. 17.915 − 679 =
18. 18.538 − 227 =
19. 19.507 − 199 =
20. 20.852 − 199 =
21. 21.491 − 399 =
22. 22.925 − 798 =
23. 23.418 − 298 =
24. 24.916 − 397 =
25. 25.753 − 357 =
26. 26.874 − 598 =
27. 27.828 − 798 =
28. 28.747 − 697 =
29. 29.938 − 698 =
30. 30.810 − 298 =
31. 31.775 − 399 =
32. 32.544 − 378 =
33. 33.924 − 427 =
34. 34.890 − 797 =
35. 35.815 − 248 =
36. 36.965 − 797 =
37. 37.841 − 797 =
38. 38.364 − 299 =
39. 39.686 − 289 =
40. 40.890 − 498 =

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