Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 844 · 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. 1.525 − 498 =
2. 2.858 − 498 =
3. 3.887 − 698 =
4. 4.736 − 189 =
5. 5.407 − 197 =
6. 6.655 − 399 =
7. 7.419 − 327 =
8. 8.625 − 228 =
9. 9.440 − 299 =
10. 10.768 − 699 =
11. 11.375 − 127 =
12. 12.829 − 397 =
13. 13.299 − 197 =
14. 14.913 − 597 =
15. 15.969 − 598 =
16. 16.419 − 199 =
17. 17.839 − 639 =
18. 18.855 − 598 =
19. 19.498 − 248 =
20. 20.309 − 229 =
21. 21.367 − 298 =
22. 22.454 − 198 =
23. 23.612 − 599 =
24. 24.676 − 597 =
25. 25.703 − 679 =
26. 26.750 − 567 =
27. 27.721 − 699 =
28. 28.856 − 499 =
29. 29.357 − 259 =
30. 30.542 − 458 =
31. 31.374 − 197 =
32. 32.976 − 797 =
33. 33.904 − 699 =
34. 34.705 − 198 =
35. 35.645 − 559 =
36. 36.684 − 599 =
37. 37.911 − 307 =
38. 38.514 − 298 =
39. 39.591 − 399 =
40. 40.184 − 118 =

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