Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 318 · 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. 1.852 − 457 =
2. 2.768 − 178 =
3. 3.766 − 298 =
4. 4.935 − 687 =
5. 5.789 − 389 =
6. 6.909 − 198 =
7. 7.259 − 147 =
8. 8.905 − 529 =
9. 9.735 − 569 =
10. 10.812 − 168 =
11. 11.769 − 559 =
12. 12.973 − 297 =
13. 13.612 − 598 =
14. 14.867 − 497 =
15. 15.960 − 798 =
16. 16.928 − 418 =
17. 17.637 − 597 =
18. 18.765 − 497 =
19. 19.690 − 597 =
20. 20.958 − 489 =
21. 21.834 − 547 =
22. 22.998 − 688 =
23. 23.905 − 658 =
24. 24.409 − 199 =
25. 25.886 − 427 =
26. 26.732 − 297 =
27. 27.787 − 699 =
28. 28.848 − 629 =
29. 29.672 − 417 =
30. 30.756 − 398 =
31. 31.281 − 198 =
32. 32.883 − 698 =
33. 33.563 − 397 =
34. 34.976 − 598 =
35. 35.954 − 697 =
36. 36.869 − 699 =
37. 37.872 − 797 =
38. 38.581 − 258 =
39. 39.466 − 297 =
40. 40.854 − 498 =

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