Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 602 · 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. 1.921 − 689 =
2. 2.759 − 298 =
3. 3.994 − 598 =
4. 4.655 − 499 =
5. 5.786 − 697 =
6. 6.991 − 389 =
7. 7.971 − 597 =
8. 8.668 − 598 =
9. 9.500 − 147 =
10. 10.605 − 117 =
11. 11.794 − 699 =
12. 12.969 − 498 =
13. 13.661 − 578 =
14. 14.497 − 198 =
15. 15.680 − 618 =
16. 16.695 − 239 =
17. 17.885 − 169 =
18. 18.476 − 308 =
19. 19.432 − 189 =
20. 20.746 − 327 =
21. 21.984 − 389 =
22. 22.611 − 498 =
23. 23.973 − 667 =
24. 24.691 − 589 =
25. 25.787 − 607 =
26. 26.484 − 199 =
27. 27.478 − 297 =
28. 28.772 − 699 =
29. 29.948 − 797 =
30. 30.666 − 217 =
31. 31.861 − 799 =
32. 32.987 − 649 =
33. 33.921 − 697 =
34. 34.895 − 599 =
35. 35.755 − 277 =
36. 36.913 − 559 =
37. 37.977 − 499 =
38. 38.611 − 499 =
39. 39.733 − 499 =
40. 40.763 − 499 =

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