Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 486 · 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. 1.959 − 297 =
2. 2.922 − 699 =
3. 3.961 − 229 =
4. 4.999 − 797 =
5. 5.667 − 299 =
6. 6.643 − 199 =
7. 7.581 − 539 =
8. 8.563 − 197 =
9. 9.877 − 477 =
10. 10.863 − 458 =
11. 11.577 − 207 =
12. 12.951 − 627 =
13. 13.699 − 177 =
14. 14.834 − 319 =
15. 15.983 − 497 =
16. 16.939 − 799 =
17. 17.488 − 398 =
18. 18.869 − 307 =
19. 19.815 − 697 =
20. 20.998 − 799 =
21. 21.908 − 298 =
22. 22.983 − 597 =
23. 23.759 − 297 =
24. 24.550 − 217 =
25. 25.446 − 419 =
26. 26.857 − 487 =
27. 27.582 − 478 =
28. 28.715 − 397 =
29. 29.929 − 698 =
30. 30.574 − 549 =
31. 31.409 − 199 =
32. 32.789 − 599 =
33. 33.607 − 498 =
34. 34.930 − 599 =
35. 35.919 − 199 =
36. 36.908 − 158 =
37. 37.586 − 457 =
38. 38.548 − 198 =
39. 39.816 − 179 =
40. 40.935 − 329 =

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