Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 295 · 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. 1.745 − 677 =
2. 2.734 − 199 =
3. 3.548 − 399 =
4. 4.534 − 399 =
5. 5.487 − 409 =
6. 6.957 − 698 =
7. 7.747 − 697 =
8. 8.895 − 548 =
9. 9.697 − 657 =
10. 10.736 − 427 =
11. 11.638 − 598 =
12. 12.998 − 297 =
13. 13.763 − 597 =
14. 14.634 − 417 =
15. 15.795 − 699 =
16. 16.997 − 697 =
17. 17.835 − 798 =
18. 18.444 − 299 =
19. 19.524 − 298 =
20. 20.570 − 549 =
21. 21.911 − 399 =
22. 22.553 − 218 =
23. 23.868 − 448 =
24. 24.933 − 639 =
25. 25.965 − 639 =
26. 26.633 − 598 =
27. 27.325 − 237 =
28. 28.715 − 399 =
29. 29.714 − 189 =
30. 30.837 − 799 =
31. 31.619 − 497 =
32. 32.531 − 397 =
33. 33.961 − 268 =
34. 34.935 − 697 =
35. 35.539 − 399 =
36. 36.692 − 398 =
37. 37.830 − 368 =
38. 38.661 − 598 =
39. 39.813 − 177 =
40. 40.914 − 297 =

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