Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 71 · 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. 1.468 − 299 =
2. 2.568 − 498 =
3. 3.565 − 199 =
4. 4.934 − 517 =
5. 5.803 − 599 =
6. 6.327 − 219 =
7. 7.680 − 468 =
8. 8.769 − 678 =
9. 9.696 − 498 =
10. 10.635 − 298 =
11. 11.862 − 699 =
12. 12.668 − 497 =
13. 13.722 − 398 =
14. 14.713 − 599 =
15. 15.873 − 469 =
16. 16.860 − 799 =
17. 17.770 − 698 =
18. 18.750 − 609 =
19. 19.847 − 229 =
20. 20.968 − 797 =
21. 21.656 − 297 =
22. 22.392 − 199 =
23. 23.685 − 499 =
24. 24.779 − 639 =
25. 25.854 − 599 =
26. 26.800 − 448 =
27. 27.390 − 137 =
28. 28.758 − 617 =
29. 29.818 − 568 =
30. 30.842 − 227 =
31. 31.645 − 599 =
32. 32.633 − 517 =
33. 33.751 − 698 =
34. 34.695 − 599 =
35. 35.523 − 498 =
36. 36.601 − 159 =
37. 37.952 − 799 =
38. 38.674 − 638 =
39. 39.964 − 198 =
40. 40.717 − 409 =

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