Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 724 · 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. 1.477 − 298 =
2. 2.993 − 499 =
3. 3.926 − 597 =
4. 4.699 − 667 =
5. 5.659 − 547 =
6. 6.596 − 458 =
7. 7.976 − 157 =
8. 8.832 − 797 =
9. 9.517 − 298 =
10. 10.757 − 698 =
11. 11.469 − 448 =
12. 12.896 − 697 =
13. 13.783 − 568 =
14. 14.598 − 529 =
15. 15.799 − 668 =
16. 16.491 − 468 =
17. 17.986 − 799 =
18. 18.508 − 397 =
19. 19.963 − 598 =
20. 20.350 − 249 =
21. 21.785 − 289 =
22. 22.850 − 498 =
23. 23.538 − 508 =
24. 24.867 − 797 =
25. 25.410 − 198 =
26. 26.601 − 438 =
27. 27.647 − 417 =
28. 28.705 − 628 =
29. 29.741 − 498 =
30. 30.995 − 499 =
31. 31.332 − 159 =
32. 32.565 − 499 =
33. 33.658 − 537 =
34. 34.825 − 799 =
35. 35.886 − 448 =
36. 36.586 − 529 =
37. 37.880 − 798 =
38. 38.522 − 499 =
39. 39.691 − 288 =
40. 40.607 − 379 =

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