Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 78 · 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. 1.932 − 198 =
2. 2.410 − 307 =
3. 3.529 − 497 =
4. 4.794 − 649 =
5. 5.834 − 397 =
6. 6.872 − 209 =
7. 7.577 − 209 =
8. 8.174 − 159 =
9. 9.881 − 599 =
10. 10.783 − 399 =
11. 11.670 − 599 =
12. 12.876 − 798 =
13. 13.845 − 798 =
14. 14.528 − 298 =
15. 15.899 − 367 =
16. 16.901 − 157 =
17. 17.715 − 617 =
18. 18.454 − 298 =
19. 19.358 − 328 =
20. 20.674 − 298 =
21. 21.385 − 199 =
22. 22.450 − 299 =
23. 23.974 − 297 =
24. 24.824 − 298 =
25. 25.813 − 799 =
26. 26.643 − 299 =
27. 27.695 − 307 =
28. 28.500 − 198 =
29. 29.850 − 288 =
30. 30.914 − 498 =
31. 31.762 − 189 =
32. 32.790 − 438 =
33. 33.888 − 198 =
34. 34.674 − 308 =
35. 35.844 − 799 =
36. 36.767 − 598 =
37. 37.906 − 298 =
38. 38.217 − 197 =
39. 39.894 − 399 =
40. 40.852 − 799 =

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