Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 744 · 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. 1.749 − 679 =
2. 2.294 − 169 =
3. 3.919 − 668 =
4. 4.161 − 139 =
5. 5.999 − 599 =
6. 6.842 − 497 =
7. 7.698 − 497 =
8. 8.535 − 498 =
9. 9.637 − 199 =
10. 10.851 − 199 =
11. 11.492 − 397 =
12. 12.408 − 198 =
13. 13.997 − 799 =
14. 14.789 − 599 =
15. 15.401 − 299 =
16. 16.634 − 399 =
17. 17.912 − 137 =
18. 18.484 − 197 =
19. 19.718 − 298 =
20. 20.714 − 299 =
21. 21.929 − 457 =
22. 22.881 − 299 =
23. 23.764 − 697 =
24. 24.374 − 249 =
25. 25.808 − 517 =
26. 26.992 − 799 =
27. 27.412 − 199 =
28. 28.779 − 677 =
29. 29.961 − 797 =
30. 30.908 − 198 =
31. 31.928 − 609 =
32. 32.531 − 299 =
33. 33.512 − 298 =
34. 34.885 − 167 =
35. 35.500 − 299 =
36. 36.779 − 599 =
37. 37.336 − 157 =
38. 38.841 − 697 =
39. 39.520 − 377 =
40. 40.415 − 197 =

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