Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 593 · 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. 1.768 − 317 =
2. 2.456 − 398 =
3. 3.992 − 499 =
4. 4.941 − 447 =
5. 5.582 − 489 =
6. 6.925 − 397 =
7. 7.341 − 197 =
8. 8.724 − 698 =
9. 9.710 − 298 =
10. 10.549 − 519 =
11. 11.965 − 439 =
12. 12.833 − 798 =
13. 13.802 − 598 =
14. 14.858 − 289 =
15. 15.484 − 398 =
16. 16.935 − 629 =
17. 17.857 − 698 =
18. 18.982 − 697 =
19. 19.629 − 199 =
20. 20.763 − 698 =
21. 21.604 − 587 =
22. 22.524 − 197 =
23. 23.930 − 279 =
24. 24.521 − 197 =
25. 25.430 − 257 =
26. 26.758 − 697 =
27. 27.924 − 398 =
28. 28.795 − 397 =
29. 29.824 − 697 =
30. 30.642 − 528 =
31. 31.939 − 697 =
32. 32.700 − 139 =
33. 33.983 − 397 =
34. 34.721 − 398 =
35. 35.765 − 499 =
36. 36.867 − 199 =
37. 37.494 − 217 =
38. 38.571 − 477 =
39. 39.680 − 298 =
40. 40.946 − 458 =

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