Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 758 · 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. 1.483 − 199 =
2. 2.996 − 699 =
3. 3.934 − 668 =
4. 4.819 − 597 =
5. 5.769 − 497 =
6. 6.919 − 297 =
7. 7.752 − 697 =
8. 8.926 − 697 =
9. 9.470 − 449 =
10. 10.871 − 407 =
11. 11.941 − 598 =
12. 12.814 − 199 =
13. 13.996 − 599 =
14. 14.996 − 198 =
15. 15.867 − 197 =
16. 16.560 − 299 =
17. 17.533 − 499 =
18. 18.526 − 499 =
19. 19.992 − 799 =
20. 20.226 − 197 =
21. 21.852 − 697 =
22. 22.917 − 198 =
23. 23.685 − 498 =
24. 24.819 − 399 =
25. 25.682 − 209 =
26. 26.599 − 179 =
27. 27.740 − 699 =
28. 28.386 − 297 =
29. 29.704 − 499 =
30. 30.871 − 539 =
31. 31.437 − 307 =
32. 32.329 − 199 =
33. 33.746 − 278 =
34. 34.586 − 548 =
35. 35.696 − 238 =
36. 36.816 − 599 =
37. 37.560 − 497 =
38. 38.728 − 697 =
39. 39.852 − 477 =
40. 40.928 − 397 =

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