Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 571 · 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. 1.404 − 369 =
2. 2.439 − 397 =
3. 3.247 − 197 =
4. 4.376 − 279 =
5. 5.872 − 299 =
6. 6.918 − 118 =
7. 7.919 − 499 =
8. 8.729 − 697 =
9. 9.292 − 179 =
10. 10.373 − 217 =
11. 11.863 − 218 =
12. 12.713 − 397 =
13. 13.677 − 127 =
14. 14.448 − 199 =
15. 15.988 − 799 =
16. 16.451 − 428 =
17. 17.874 − 698 =
18. 18.889 − 697 =
19. 19.680 − 197 =
20. 20.526 − 348 =
21. 21.888 − 297 =
22. 22.514 − 297 =
23. 23.728 − 268 =
24. 24.953 − 698 =
25. 25.576 − 199 =
26. 26.285 − 148 =
27. 27.904 − 499 =
28. 28.908 − 188 =
29. 29.781 − 697 =
30. 30.967 − 519 =
31. 31.546 − 389 =
32. 32.803 − 348 =
33. 33.599 − 198 =
34. 34.699 − 589 =
35. 35.790 − 639 =
36. 36.851 − 798 =
37. 37.861 − 489 =
38. 38.780 − 697 =
39. 39.975 − 639 =
40. 40.834 − 527 =

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