Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 249 · 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. 1.234 − 127 =
2. 2.751 − 697 =
3. 3.654 − 599 =
4. 4.509 − 387 =
5. 5.780 − 699 =
6. 6.744 − 497 =
7. 7.965 − 798 =
8. 8.871 − 197 =
9. 9.890 − 297 =
10. 10.832 − 297 =
11. 11.441 − 147 =
12. 12.424 − 309 =
13. 13.765 − 407 =
14. 14.521 − 198 =
15. 15.881 − 599 =
16. 16.826 − 397 =
17. 17.822 − 169 =
18. 18.648 − 599 =
19. 19.863 − 797 =
20. 20.688 − 497 =
21. 21.857 − 357 =
22. 22.978 − 698 =
23. 23.598 − 498 =
24. 24.470 − 408 =
25. 25.963 − 498 =
26. 26.859 − 597 =
27. 27.802 − 528 =
28. 28.814 − 377 =
29. 29.940 − 798 =
30. 30.229 − 198 =
31. 31.676 − 409 =
32. 32.566 − 498 =
33. 33.813 − 589 =
34. 34.682 − 497 =
35. 35.866 − 798 =
36. 36.635 − 597 =
37. 37.903 − 608 =
38. 38.844 − 617 =
39. 39.812 − 798 =
40. 40.658 − 418 =

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