Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 745 · 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. 1.465 − 248 =
2. 2.801 − 347 =
3. 3.902 − 698 =
4. 4.774 − 198 =
5. 5.640 − 547 =
6. 6.654 − 499 =
7. 7.331 − 198 =
8. 8.941 − 368 =
9. 9.856 − 498 =
10. 10.400 − 227 =
11. 11.397 − 299 =
12. 12.541 − 277 =
13. 13.925 − 209 =
14. 14.939 − 127 =
15. 15.590 − 168 =
16. 16.592 − 499 =
17. 17.595 − 497 =
18. 18.848 − 368 =
19. 19.796 − 408 =
20. 20.463 − 229 =
21. 21.459 − 139 =
22. 22.774 − 697 =
23. 23.319 − 249 =
24. 24.524 − 497 =
25. 25.575 − 297 =
26. 26.799 − 499 =
27. 27.863 − 589 =
28. 28.257 − 197 =
29. 29.890 − 469 =
30. 30.954 − 498 =
31. 31.972 − 699 =
32. 32.886 − 599 =
33. 33.539 − 297 =
34. 34.955 − 197 =
35. 35.746 − 567 =
36. 36.828 − 199 =
37. 37.721 − 199 =
38. 38.827 − 297 =
39. 39.584 − 398 =
40. 40.835 − 269 =

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