Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 576 · 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. 1.809 − 619 =
2. 2.887 − 199 =
3. 3.169 − 119 =
4. 4.519 − 289 =
5. 5.944 − 429 =
6. 6.823 − 698 =
7. 7.510 − 319 =
8. 8.584 − 197 =
9. 9.449 − 208 =
10. 10.739 − 497 =
11. 11.983 − 798 =
12. 12.627 − 199 =
13. 13.648 − 359 =
14. 14.551 − 197 =
15. 15.418 − 389 =
16. 16.651 − 199 =
17. 17.827 − 299 =
18. 18.602 − 377 =
19. 19.923 − 649 =
20. 20.853 − 797 =
21. 21.726 − 597 =
22. 22.975 − 499 =
23. 23.571 − 199 =
24. 24.592 − 578 =
25. 25.678 − 179 =
26. 26.996 − 279 =
27. 27.866 − 698 =
28. 28.299 − 277 =
29. 29.585 − 397 =
30. 30.619 − 498 =
31. 31.905 − 498 =
32. 32.420 − 398 =
33. 33.862 − 598 =
34. 34.584 − 457 =
35. 35.810 − 238 =
36. 36.755 − 599 =
37. 37.416 − 398 =
38. 38.849 − 499 =
39. 39.949 − 798 =
40. 40.937 − 447 =

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