Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 338 · 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 − 497 =
2. 2.568 − 439 =
3. 3.954 − 798 =
4. 4.617 − 498 =
5. 5.696 − 427 =
6. 6.446 − 409 =
7. 7.621 − 399 =
8. 8.726 − 518 =
9. 9.814 − 647 =
10. 10.850 − 498 =
11. 11.812 − 799 =
12. 12.476 − 299 =
13. 13.740 − 597 =
14. 14.320 − 219 =
15. 15.837 − 799 =
16. 16.347 − 299 =
17. 17.867 − 799 =
18. 18.625 − 289 =
19. 19.579 − 489 =
20. 20.732 − 599 =
21. 21.570 − 189 =
22. 22.344 − 297 =
23. 23.440 − 268 =
24. 24.768 − 698 =
25. 25.334 − 297 =
26. 26.748 − 697 =
27. 27.965 − 418 =
28. 28.992 − 609 =
29. 29.889 − 498 =
30. 30.894 − 599 =
31. 31.488 − 397 =
32. 32.845 − 398 =
33. 33.783 − 327 =
34. 34.264 − 147 =
35. 35.752 − 698 =
36. 36.663 − 238 =
37. 37.837 − 678 =
38. 38.883 − 399 =
39. 39.868 − 169 =
40. 40.437 − 307 =

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