Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 384 · 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. 1.861 − 309 =
2. 2.908 − 219 =
3. 3.389 − 199 =
4. 4.739 − 499 =
5. 5.539 − 367 =
6. 6.760 − 577 =
7. 7.611 − 587 =
8. 8.698 − 638 =
9. 9.814 − 798 =
10. 10.419 − 239 =
11. 11.447 − 209 =
12. 12.919 − 297 =
13. 13.656 − 118 =
14. 14.801 − 399 =
15. 15.741 − 689 =
16. 16.898 − 797 =
17. 17.768 − 679 =
18. 18.636 − 397 =
19. 19.892 − 437 =
20. 20.914 − 698 =
21. 21.336 − 199 =
22. 22.872 − 217 =
23. 23.899 − 589 =
24. 24.930 − 599 =
25. 25.474 − 198 =
26. 26.783 − 618 =
27. 27.697 − 137 =
28. 28.831 − 597 =
29. 29.883 − 699 =
30. 30.914 − 688 =
31. 31.691 − 189 =
32. 32.792 − 699 =
33. 33.943 − 799 =
34. 34.911 − 449 =
35. 35.307 − 157 =
36. 36.769 − 499 =
37. 37.640 − 538 =
38. 38.631 − 419 =
39. 39.970 − 547 =
40. 40.523 − 499 =

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