Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 805 · 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. 1.938 − 127 =
2. 2.887 − 528 =
3. 3.714 − 298 =
4. 4.421 − 399 =
5. 5.791 − 548 =
6. 6.928 − 199 =
7. 7.734 − 298 =
8. 8.976 − 799 =
9. 9.572 − 499 =
10. 10.954 − 147 =
11. 11.985 − 797 =
12. 12.693 − 397 =
13. 13.505 − 298 =
14. 14.602 − 458 =
15. 15.832 − 799 =
16. 16.980 − 399 =
17. 17.793 − 599 =
18. 18.523 − 387 =
19. 19.488 − 407 =
20. 20.866 − 798 =
21. 21.796 − 397 =
22. 22.700 − 199 =
23. 23.503 − 297 =
24. 24.631 − 597 =
25. 25.434 − 159 =
26. 26.673 − 538 =
27. 27.712 − 577 =
28. 28.341 − 298 =
29. 29.605 − 528 =
30. 30.404 − 129 =
31. 31.729 − 497 =
32. 32.814 − 687 =
33. 33.793 − 597 =
34. 34.541 − 399 =
35. 35.242 − 198 =
36. 36.936 − 229 =
37. 37.775 − 179 =
38. 38.922 − 557 =
39. 39.818 − 189 =
40. 40.923 − 298 =

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