Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 211 · 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. 1.954 − 198 =
2. 2.962 − 398 =
3. 3.903 − 307 =
4. 4.400 − 297 =
5. 5.824 − 627 =
6. 6.522 − 249 =
7. 7.787 − 599 =
8. 8.479 − 137 =
9. 9.611 − 399 =
10. 10.437 − 377 =
11. 11.234 − 188 =
12. 12.688 − 297 =
13. 13.978 − 799 =
14. 14.736 − 547 =
15. 15.717 − 699 =
16. 16.714 − 499 =
17. 17.248 − 198 =
18. 18.519 − 297 =
19. 19.370 − 299 =
20. 20.233 − 198 =
21. 21.985 − 399 =
22. 22.544 − 178 =
23. 23.477 − 269 =
24. 24.786 − 499 =
25. 25.199 − 139 =
26. 26.676 − 239 =
27. 27.497 − 477 =
28. 28.656 − 227 =
29. 29.430 − 199 =
30. 30.245 − 218 =
31. 31.922 − 598 =
32. 32.416 − 197 =
33. 33.758 − 539 =
34. 34.635 − 497 =
35. 35.915 − 598 =
36. 36.777 − 698 =
37. 37.886 − 697 =
38. 38.812 − 797 =
39. 39.779 − 697 =
40. 40.973 − 657 =

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