Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 128 · 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. 1.883 − 698 =
2. 2.900 − 658 =
3. 3.427 − 397 =
4. 4.613 − 598 =
5. 5.640 − 397 =
6. 6.349 − 128 =
7. 7.797 − 199 =
8. 8.790 − 499 =
9. 9.922 − 799 =
10. 10.475 − 399 =
11. 11.778 − 368 =
12. 12.830 − 797 =
13. 13.749 − 698 =
14. 14.792 − 388 =
15. 15.652 − 599 =
16. 16.876 − 567 =
17. 17.483 − 118 =
18. 18.838 − 399 =
19. 19.601 − 429 =
20. 20.242 − 227 =
21. 21.546 − 309 =
22. 22.783 − 297 =
23. 23.668 − 397 =
24. 24.940 − 697 =
25. 25.900 − 697 =
26. 26.662 − 257 =
27. 27.438 − 199 =
28. 28.744 − 397 =
29. 29.651 − 519 =
30. 30.893 − 499 =
31. 31.737 − 237 =
32. 32.871 − 797 =
33. 33.506 − 159 =
34. 34.816 − 588 =
35. 35.439 − 399 =
36. 36.685 − 198 =
37. 37.517 − 167 =
38. 38.902 − 798 =
39. 39.759 − 399 =
40. 40.189 − 118 =

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