Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 774 · 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. 1.902 − 799 =
2. 2.666 − 298 =
3. 3.383 − 229 =
4. 4.908 − 799 =
5. 5.743 − 697 =
6. 6.611 − 258 =
7. 7.918 − 199 =
8. 8.885 − 699 =
9. 9.475 − 297 =
10. 10.630 − 157 =
11. 11.608 − 399 =
12. 12.519 − 498 =
13. 13.641 − 298 =
14. 14.759 − 567 =
15. 15.837 − 797 =
16. 16.879 − 797 =
17. 17.686 − 597 =
18. 18.841 − 197 =
19. 19.785 − 698 =
20. 20.917 − 398 =
21. 21.487 − 399 =
22. 22.769 − 388 =
23. 23.719 − 229 =
24. 24.780 − 299 =
25. 25.765 − 599 =
26. 26.837 − 668 =
27. 27.888 − 699 =
28. 28.662 − 297 =
29. 29.818 − 298 =
30. 30.989 − 699 =
31. 31.686 − 398 =
32. 32.522 − 227 =
33. 33.723 − 399 =
34. 34.576 − 507 =
35. 35.913 − 497 =
36. 36.875 − 319 =
37. 37.666 − 578 =
38. 38.930 − 397 =
39. 39.692 − 618 =
40. 40.998 − 617 =

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