Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 202 · 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. 1.941 − 797 =
2. 2.816 − 198 =
3. 3.900 − 169 =
4. 4.842 − 559 =
5. 5.860 − 497 =
6. 6.801 − 179 =
7. 7.497 − 267 =
8. 8.979 − 687 =
9. 9.895 − 599 =
10. 10.803 − 697 =
11. 11.996 − 398 =
12. 12.945 − 599 =
13. 13.973 − 197 =
14. 14.901 − 498 =
15. 15.697 − 438 =
16. 16.478 − 299 =
17. 17.563 − 297 =
18. 18.795 − 227 =
19. 19.793 − 499 =
20. 20.793 − 698 =
21. 21.746 − 658 =
22. 22.963 − 699 =
23. 23.441 − 227 =
24. 24.645 − 398 =
25. 25.734 − 619 =
26. 26.912 − 797 =
27. 27.943 − 618 =
28. 28.612 − 137 =
29. 29.507 − 399 =
30. 30.793 − 289 =
31. 31.508 − 197 =
32. 32.478 − 298 =
33. 33.882 − 799 =
34. 34.665 − 328 =
35. 35.911 − 398 =
36. 36.600 − 469 =
37. 37.568 − 197 =
38. 38.913 − 598 =
39. 39.922 − 497 =
40. 40.674 − 298 =

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