Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 175 · 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. 1.581 − 457 =
2. 2.794 − 319 =
3. 3.776 − 458 =
4. 4.616 − 598 =
5. 5.496 − 198 =
6. 6.936 − 597 =
7. 7.293 − 197 =
8. 8.465 − 397 =
9. 9.875 − 527 =
10. 10.723 − 437 =
11. 11.529 − 299 =
12. 12.939 − 499 =
13. 13.488 − 299 =
14. 14.320 − 228 =
15. 15.685 − 567 =
16. 16.727 − 278 =
17. 17.742 − 398 =
18. 18.770 − 499 =
19. 19.909 − 599 =
20. 20.958 − 197 =
21. 21.857 − 697 =
22. 22.852 − 597 =
23. 23.425 − 399 =
24. 24.792 − 217 =
25. 25.653 − 298 =
26. 26.862 − 499 =
27. 27.780 − 629 =
28. 28.927 − 499 =
29. 29.511 − 299 =
30. 30.870 − 437 =
31. 31.859 − 618 =
32. 32.549 − 478 =
33. 33.559 − 398 =
34. 34.896 − 248 =
35. 35.354 − 299 =
36. 36.951 − 798 =
37. 37.415 − 238 =
38. 38.707 − 598 =
39. 39.774 − 697 =
40. 40.764 − 298 =

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