Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 179 · 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. 1.916 − 618 =
2. 2.545 − 299 =
3. 3.766 − 299 =
4. 4.489 − 197 =
5. 5.953 − 598 =
6. 6.826 − 497 =
7. 7.714 − 638 =
8. 8.458 − 298 =
9. 9.592 − 287 =
10. 10.921 − 198 =
11. 11.792 − 298 =
12. 12.797 − 649 =
13. 13.443 − 398 =
14. 14.598 − 199 =
15. 15.339 − 198 =
16. 16.873 − 699 =
17. 17.873 − 429 =
18. 18.808 − 199 =
19. 19.933 − 467 =
20. 20.696 − 468 =
21. 21.595 − 499 =
22. 22.427 − 198 =
23. 23.944 − 398 =
24. 24.751 − 668 =
25. 25.866 − 697 =
26. 26.514 − 369 =
27. 27.900 − 799 =
28. 28.822 − 469 =
29. 29.706 − 497 =
30. 30.833 − 239 =
31. 31.584 − 399 =
32. 32.830 − 398 =
33. 33.829 − 298 =
34. 34.912 − 628 =
35. 35.761 − 199 =
36. 36.658 − 397 =
37. 37.476 − 249 =
38. 38.521 − 399 =
39. 39.262 − 229 =
40. 40.690 − 418 =

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