Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 912 · 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. 1.837 − 799 =
2. 2.991 − 589 =
3. 3.731 − 599 =
4. 4.810 − 597 =
5. 5.707 − 249 =
6. 6.631 − 598 =
7. 7.971 − 568 =
8. 8.305 − 197 =
9. 9.641 − 599 =
10. 10.724 − 157 =
11. 11.880 − 297 =
12. 12.398 − 259 =
13. 13.738 − 658 =
14. 14.885 − 397 =
15. 15.763 − 697 =
16. 16.707 − 599 =
17. 17.297 − 197 =
18. 18.571 − 459 =
19. 19.832 − 309 =
20. 20.520 − 348 =
21. 21.867 − 558 =
22. 22.941 − 199 =
23. 23.927 − 238 =
24. 24.825 − 799 =
25. 25.549 − 197 =
26. 26.686 − 297 =
27. 27.550 − 498 =
28. 28.646 − 599 =
29. 29.905 − 637 =
30. 30.705 − 597 =
31. 31.421 − 397 =
32. 32.676 − 399 =
33. 33.796 − 177 =
34. 34.617 − 398 =
35. 35.853 − 627 =
36. 36.685 − 598 =
37. 37.770 − 699 =
38. 38.942 − 677 =
39. 39.815 − 397 =
40. 40.555 − 188 =

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