Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 155 · 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. 1.486 − 199 =
2. 2.772 − 699 =
3. 3.827 − 527 =
4. 4.973 − 499 =
5. 5.196 − 159 =
6. 6.818 − 597 =
7. 7.886 − 469 =
8. 8.938 − 199 =
9. 9.660 − 519 =
10. 10.958 − 799 =
11. 11.813 − 598 =
12. 12.500 − 199 =
13. 13.698 − 499 =
14. 14.994 − 399 =
15. 15.795 − 297 =
16. 16.455 − 188 =
17. 17.916 − 167 =
18. 18.964 − 699 =
19. 19.821 − 658 =
20. 20.752 − 698 =
21. 21.612 − 598 =
22. 22.725 − 598 =
23. 23.695 − 538 =
24. 24.835 − 797 =
25. 25.820 − 297 =
26. 26.576 − 317 =
27. 27.851 − 799 =
28. 28.333 − 178 =
29. 29.974 − 648 =
30. 30.804 − 598 =
31. 31.819 − 797 =
32. 32.524 − 299 =
33. 33.833 − 699 =
34. 34.922 − 539 =
35. 35.570 − 187 =
36. 36.576 − 498 =
37. 37.978 − 797 =
38. 38.613 − 417 =
39. 39.934 − 599 =
40. 40.816 − 398 =

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