Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 250 · 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. 1.379 − 298 =
2. 2.919 − 537 =
3. 3.998 − 597 =
4. 4.336 − 309 =
5. 5.491 − 407 =
6. 6.396 − 138 =
7. 7.640 − 609 =
8. 8.690 − 499 =
9. 9.977 − 799 =
10. 10.804 − 227 =
11. 11.600 − 138 =
12. 12.266 − 199 =
13. 13.727 − 497 =
14. 14.763 − 148 =
15. 15.588 − 537 =
16. 16.381 − 197 =
17. 17.972 − 797 =
18. 18.832 − 327 =
19. 19.747 − 599 =
20. 20.354 − 308 =
21. 21.689 − 667 =
22. 22.867 − 699 =
23. 23.560 − 488 =
24. 24.950 − 198 =
25. 25.898 − 678 =
26. 26.782 − 697 =
27. 27.694 − 558 =
28. 28.316 − 199 =
29. 29.885 − 427 =
30. 30.691 − 629 =
31. 31.553 − 499 =
32. 32.793 − 658 =
33. 33.631 − 297 =
34. 34.784 − 687 =
35. 35.961 − 699 =
36. 36.813 − 798 =
37. 37.429 − 397 =
38. 38.962 − 598 =
39. 39.913 − 799 =
40. 40.704 − 397 =

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