Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 29 · 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. 1.849 − 799 =
2. 2.990 − 699 =
3. 3.982 − 797 =
4. 4.784 − 467 =
5. 5.854 − 488 =
6. 6.330 − 299 =
7. 7.910 − 509 =
8. 8.633 − 599 =
9. 9.809 − 198 =
10. 10.700 − 529 =
11. 11.959 − 497 =
12. 12.821 − 198 =
13. 13.987 − 528 =
14. 14.675 − 658 =
15. 15.690 − 198 =
16. 16.825 − 798 =
17. 17.712 − 567 =
18. 18.383 − 299 =
19. 19.880 − 797 =
20. 20.877 − 598 =
21. 21.897 − 167 =
22. 22.499 − 399 =
23. 23.959 − 297 =
24. 24.863 − 297 =
25. 25.998 − 798 =
26. 26.937 − 519 =
27. 27.475 − 177 =
28. 28.691 − 598 =
29. 29.968 − 199 =
30. 30.725 − 167 =
31. 31.992 − 799 =
32. 32.454 − 267 =
33. 33.779 − 198 =
34. 34.782 − 398 =
35. 35.774 − 698 =
36. 36.814 − 599 =
37. 37.896 − 797 =
38. 38.853 − 698 =
39. 39.374 − 229 =
40. 40.565 − 499 =

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