Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 751 · 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. 1.825 − 427 =
2. 2.742 − 619 =
3. 3.809 − 499 =
4. 4.722 − 228 =
5. 5.631 − 497 =
6. 6.969 − 798 =
7. 7.854 − 299 =
8. 8.440 − 239 =
9. 9.863 − 559 =
10. 10.585 − 567 =
11. 11.652 − 589 =
12. 12.905 − 698 =
13. 13.655 − 289 =
14. 14.890 − 208 =
15. 15.236 − 197 =
16. 16.867 − 798 =
17. 17.726 − 358 =
18. 18.342 − 199 =
19. 19.713 − 498 =
20. 20.556 − 407 =
21. 21.483 − 298 =
22. 22.569 − 339 =
23. 23.583 − 299 =
24. 24.375 − 227 =
25. 25.979 − 599 =
26. 26.525 − 429 =
27. 27.925 − 579 =
28. 28.649 − 317 =
29. 29.928 − 489 =
30. 30.506 − 299 =
31. 31.966 − 197 =
32. 32.745 − 499 =
33. 33.717 − 697 =
34. 34.747 − 297 =
35. 35.611 − 208 =
36. 36.917 − 699 =
37. 37.877 − 569 =
38. 38.513 − 497 =
39. 39.283 − 198 =
40. 40.329 − 237 =

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