Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 449 · 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. 1.955 − 588 =
2. 2.655 − 639 =
3. 3.977 − 387 =
4. 4.636 − 498 =
5. 5.508 − 278 =
6. 6.971 − 209 =
7. 7.189 − 127 =
8. 8.861 − 797 =
9. 9.531 − 467 =
10. 10.762 − 699 =
11. 11.534 − 118 =
12. 12.636 − 297 =
13. 13.791 − 647 =
14. 14.839 − 699 =
15. 15.654 − 529 =
16. 16.577 − 197 =
17. 17.919 − 399 =
18. 18.577 − 297 =
19. 19.992 − 598 =
20. 20.445 − 299 =
21. 21.868 − 298 =
22. 22.995 − 598 =
23. 23.670 − 289 =
24. 24.819 − 698 =
25. 25.486 − 219 =
26. 26.478 − 437 =
27. 27.641 − 279 =
28. 28.846 − 298 =
29. 29.739 − 299 =
30. 30.991 − 399 =
31. 31.868 − 527 =
32. 32.587 − 538 =
33. 33.773 − 299 =
34. 34.545 − 369 =
35. 35.794 − 499 =
36. 36.941 − 158 =
37. 37.569 − 348 =
38. 38.754 − 609 =
39. 39.905 − 299 =
40. 40.695 − 577 =

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