Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 564 · 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. 1.858 − 468 =
2. 2.551 − 268 =
3. 3.389 − 277 =
4. 4.904 − 399 =
5. 5.466 − 287 =
6. 6.496 − 439 =
7. 7.576 − 399 =
8. 8.284 − 149 =
9. 9.514 − 398 =
10. 10.738 − 449 =
11. 11.491 − 297 =
12. 12.996 − 699 =
13. 13.449 − 298 =
14. 14.654 − 238 =
15. 15.466 − 299 =
16. 16.952 − 529 =
17. 17.913 − 297 =
18. 18.616 − 238 =
19. 19.925 − 799 =
20. 20.961 − 399 =
21. 21.392 − 289 =
22. 22.611 − 398 =
23. 23.498 − 398 =
24. 24.979 − 799 =
25. 25.988 − 197 =
26. 26.765 − 667 =
27. 27.971 − 127 =
28. 28.933 − 799 =
29. 29.517 − 198 =
30. 30.688 − 599 =
31. 31.829 − 797 =
32. 32.941 − 197 =
33. 33.928 − 798 =
34. 34.767 − 398 =
35. 35.918 − 798 =
36. 36.667 − 599 =
37. 37.981 − 199 =
38. 38.764 − 187 =
39. 39.265 − 118 =
40. 40.538 − 349 =

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