Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 162 · 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. 1.615 − 359 =
2. 2.666 − 498 =
3. 3.492 − 188 =
4. 4.268 − 148 =
5. 5.764 − 699 =
6. 6.619 − 119 =
7. 7.641 − 398 =
8. 8.820 − 227 =
9. 9.665 − 467 =
10. 10.915 − 518 =
11. 11.972 − 398 =
12. 12.673 − 148 =
13. 13.690 − 598 =
14. 14.446 − 429 =
15. 15.385 − 199 =
16. 16.557 − 538 =
17. 17.807 − 648 =
18. 18.359 − 299 =
19. 19.835 − 799 =
20. 20.878 − 199 =
21. 21.751 − 359 =
22. 22.654 − 478 =
23. 23.968 − 368 =
24. 24.613 − 549 =
25. 25.694 − 499 =
26. 26.649 − 307 =
27. 27.676 − 597 =
28. 28.623 − 419 =
29. 29.878 − 597 =
30. 30.875 − 699 =
31. 31.756 − 697 =
32. 32.374 − 297 =
33. 33.555 − 148 =
34. 34.577 − 498 =
35. 35.744 − 298 =
36. 36.743 − 699 =
37. 37.678 − 297 =
38. 38.984 − 487 =
39. 39.653 − 597 =
40. 40.777 − 399 =

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths