Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 119 · 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. 1.701 − 299 =
2. 2.808 − 599 =
3. 3.859 − 327 =
4. 4.695 − 597 =
5. 5.991 − 388 =
6. 6.392 − 199 =
7. 7.363 − 198 =
8. 8.242 − 177 =
9. 9.885 − 698 =
10. 10.951 − 498 =
11. 11.981 − 569 =
12. 12.688 − 199 =
13. 13.754 − 247 =
14. 14.880 − 697 =
15. 15.983 − 429 =
16. 16.643 − 499 =
17. 17.307 − 117 =
18. 18.748 − 627 =
19. 19.336 − 298 =
20. 20.458 − 308 =
21. 21.785 − 398 =
22. 22.901 − 598 =
23. 23.893 − 479 =
24. 24.973 − 199 =
25. 25.511 − 297 =
26. 26.909 − 399 =
27. 27.951 − 268 =
28. 28.998 − 667 =
29. 29.822 − 388 =
30. 30.921 − 599 =
31. 31.347 − 298 =
32. 32.817 − 797 =
33. 33.819 − 699 =
34. 34.769 − 637 =
35. 35.695 − 497 =
36. 36.949 − 798 =
37. 37.631 − 599 =
38. 38.653 − 599 =
39. 39.637 − 299 =
40. 40.957 − 697 =

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