Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 118 · 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. 1.861 − 299 =
2. 2.945 − 798 =
3. 3.425 − 398 =
4. 4.731 − 598 =
5. 5.610 − 497 =
6. 6.720 − 699 =
7. 7.936 − 528 =
8. 8.771 − 699 =
9. 9.942 − 297 =
10. 10.984 − 378 =
11. 11.869 − 399 =
12. 12.628 − 399 =
13. 13.527 − 479 =
14. 14.949 − 797 =
15. 15.840 − 699 =
16. 16.731 − 697 =
17. 17.776 − 618 =
18. 18.971 − 597 =
19. 19.881 − 799 =
20. 20.420 − 397 =
21. 21.752 − 277 =
22. 22.761 − 687 =
23. 23.597 − 357 =
24. 24.610 − 427 =
25. 25.908 − 699 =
26. 26.946 − 199 =
27. 27.787 − 599 =
28. 28.593 − 397 =
29. 29.838 − 638 =
30. 30.894 − 569 =
31. 31.376 − 209 =
32. 32.542 − 198 =
33. 33.891 − 117 =
34. 34.789 − 298 =
35. 35.455 − 199 =
36. 36.532 − 118 =
37. 37.800 − 698 =
38. 38.519 − 498 =
39. 39.546 − 119 =
40. 40.904 − 678 =

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