Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 141 · 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. 1.878 − 697 =
2. 2.617 − 299 =
3. 3.898 − 398 =
4. 4.216 − 159 =
5. 5.964 − 668 =
6. 6.523 − 198 =
7. 7.968 − 298 =
8. 8.891 − 299 =
9. 9.331 − 298 =
10. 10.558 − 428 =
11. 11.958 − 599 =
12. 12.903 − 198 =
13. 13.753 − 299 =
14. 14.559 − 468 =
15. 15.354 − 309 =
16. 16.321 − 128 =
17. 17.661 − 579 =
18. 18.383 − 297 =
19. 19.821 − 799 =
20. 20.940 − 799 =
21. 21.318 − 139 =
22. 22.189 − 128 =
23. 23.662 − 599 =
24. 24.601 − 298 =
25. 25.577 − 198 =
26. 26.715 − 578 =
27. 27.686 − 548 =
28. 28.552 − 449 =
29. 29.801 − 399 =
30. 30.645 − 218 =
31. 31.912 − 597 =
32. 32.501 − 457 =
33. 33.559 − 299 =
34. 34.568 − 498 =
35. 35.937 − 697 =
36. 36.762 − 477 =
37. 37.901 − 237 =
38. 38.718 − 657 =
39. 39.564 − 229 =
40. 40.889 − 667 =

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