Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 272 · 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. 1.996 − 387 =
2. 2.900 − 299 =
3. 3.636 − 609 =
4. 4.899 − 298 =
5. 5.612 − 598 =
6. 6.701 − 198 =
7. 7.796 − 398 =
8. 8.358 − 297 =
9. 9.739 − 297 =
10. 10.457 − 398 =
11. 11.481 − 179 =
12. 12.925 − 657 =
13. 13.844 − 299 =
14. 14.864 − 199 =
15. 15.607 − 298 =
16. 16.795 − 399 =
17. 17.657 − 208 =
18. 18.923 − 698 =
19. 19.958 − 599 =
20. 20.853 − 518 =
21. 21.697 − 439 =
22. 22.335 − 197 =
23. 23.872 − 697 =
24. 24.785 − 518 =
25. 25.969 − 488 =
26. 26.567 − 499 =
27. 27.553 − 499 =
28. 28.236 − 198 =
29. 29.343 − 149 =
30. 30.643 − 439 =
31. 31.985 − 397 =
32. 32.773 − 698 =
33. 33.944 − 398 =
34. 34.958 − 399 =
35. 35.507 − 438 =
36. 36.895 − 168 =
37. 37.893 − 797 =
38. 38.284 − 197 =
39. 39.721 − 297 =
40. 40.714 − 299 =

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