Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 173 · 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. 1.971 − 698 =
2. 2.790 − 397 =
3. 3.914 − 799 =
4. 4.958 − 799 =
5. 5.665 − 398 =
6. 6.822 − 297 =
7. 7.670 − 519 =
8. 8.901 − 699 =
9. 9.721 − 199 =
10. 10.974 − 399 =
11. 11.713 − 298 =
12. 12.806 − 598 =
13. 13.935 − 549 =
14. 14.951 − 667 =
15. 15.512 − 389 =
16. 16.626 − 418 =
17. 17.755 − 499 =
18. 18.924 − 499 =
19. 19.764 − 698 =
20. 20.833 − 489 =
21. 21.665 − 137 =
22. 22.584 − 399 =
23. 23.731 − 168 =
24. 24.644 − 397 =
25. 25.757 − 438 =
26. 26.618 − 598 =
27. 27.871 − 387 =
28. 28.894 − 459 =
29. 29.331 − 199 =
30. 30.634 − 467 =
31. 31.733 − 689 =
32. 32.751 − 697 =
33. 33.722 − 699 =
34. 34.981 − 797 =
35. 35.588 − 198 =
36. 36.994 − 577 =
37. 37.318 − 278 =
38. 38.748 − 599 =
39. 39.957 − 447 =
40. 40.267 − 199 =

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