Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 389 · 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. 1.452 − 278 =
2. 2.953 − 398 =
3. 3.941 − 799 =
4. 4.652 − 367 =
5. 5.767 − 438 =
6. 6.532 − 508 =
7. 7.467 − 139 =
8. 8.862 − 799 =
9. 9.451 − 378 =
10. 10.617 − 267 =
11. 11.837 − 799 =
12. 12.793 − 398 =
13. 13.992 − 299 =
14. 14.299 − 198 =
15. 15.830 − 198 =
16. 16.871 − 227 =
17. 17.870 − 269 =
18. 18.858 − 259 =
19. 19.952 − 668 =
20. 20.613 − 498 =
21. 21.987 − 287 =
22. 22.907 − 549 =
23. 23.594 − 398 =
24. 24.813 − 297 =
25. 25.875 − 397 =
26. 26.762 − 399 =
27. 27.540 − 117 =
28. 28.819 − 797 =
29. 29.590 − 499 =
30. 30.799 − 197 =
31. 31.630 − 598 =
32. 32.644 − 379 =
33. 33.961 − 299 =
34. 34.797 − 177 =
35. 35.509 − 199 =
36. 36.946 − 199 =
37. 37.698 − 117 =
38. 38.753 − 698 =
39. 39.913 − 499 =
40. 40.895 − 319 =

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