Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 674 · 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 − 568 =
2. 2.573 − 499 =
3. 3.789 − 399 =
4. 4.777 − 598 =
5. 5.850 − 258 =
6. 6.876 − 599 =
7. 7.804 − 697 =
8. 8.327 − 199 =
9. 9.736 − 699 =
10. 10.671 − 598 =
11. 11.714 − 539 =
12. 12.763 − 397 =
13. 13.837 − 697 =
14. 14.762 − 629 =
15. 15.664 − 129 =
16. 16.743 − 198 =
17. 17.730 − 299 =
18. 18.879 − 398 =
19. 19.669 − 599 =
20. 20.660 − 319 =
21. 21.969 − 499 =
22. 22.798 − 258 =
23. 23.821 − 519 =
24. 24.908 − 699 =
25. 25.764 − 599 =
26. 26.592 − 398 =
27. 27.452 − 269 =
28. 28.667 − 478 =
29. 29.478 − 367 =
30. 30.648 − 299 =
31. 31.485 − 438 =
32. 32.691 − 297 =
33. 33.624 − 597 =
34. 34.321 − 299 =
35. 35.541 − 499 =
36. 36.874 − 497 =
37. 37.802 − 148 =
38. 38.924 − 798 =
39. 39.748 − 639 =
40. 40.218 − 198 =

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