Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 376 · 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. 1.796 − 667 =
2. 2.892 − 289 =
3. 3.550 − 297 =
4. 4.521 − 469 =
5. 5.526 − 397 =
6. 6.874 − 247 =
7. 7.619 − 198 =
8. 8.715 − 699 =
9. 9.641 − 199 =
10. 10.834 − 797 =
11. 11.842 − 798 =
12. 12.842 − 298 =
13. 13.453 − 197 =
14. 14.753 − 197 =
15. 15.619 − 297 =
16. 16.790 − 597 =
17. 17.864 − 238 =
18. 18.824 − 158 =
19. 19.975 − 518 =
20. 20.762 − 399 =
21. 21.875 − 397 =
22. 22.928 − 697 =
23. 23.649 − 497 =
24. 24.638 − 529 =
25. 25.840 − 489 =
26. 26.592 − 197 =
27. 27.608 − 577 =
28. 28.673 − 398 =
29. 29.974 − 317 =
30. 30.948 − 429 =
31. 31.607 − 349 =
32. 32.945 − 699 =
33. 33.874 − 677 =
34. 34.268 − 228 =
35. 35.991 − 797 =
36. 36.940 − 199 =
37. 37.841 − 199 =
38. 38.528 − 469 =
39. 39.442 − 197 =
40. 40.943 − 799 =

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