Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 497 · 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. 1.953 − 498 =
2. 2.465 − 127 =
3. 3.323 − 169 =
4. 4.765 − 157 =
5. 5.746 − 257 =
6. 6.814 − 657 =
7. 7.587 − 528 =
8. 8.965 − 798 =
9. 9.894 − 599 =
10. 10.867 − 297 =
11. 11.613 − 198 =
12. 12.964 − 198 =
13. 13.999 − 408 =
14. 14.923 − 299 =
15. 15.500 − 249 =
16. 16.781 − 677 =
17. 17.921 − 497 =
18. 18.655 − 499 =
19. 19.936 − 139 =
20. 20.842 − 698 =
21. 21.752 − 699 =
22. 22.428 − 398 =
23. 23.858 − 798 =
24. 24.991 − 599 =
25. 25.821 − 498 =
26. 26.881 − 798 =
27. 27.494 − 447 =
28. 28.826 − 398 =
29. 29.710 − 498 =
30. 30.719 − 598 =
31. 31.603 − 478 =
32. 32.758 − 559 =
33. 33.686 − 299 =
34. 34.840 − 697 =
35. 35.829 − 508 =
36. 36.944 − 398 =
37. 37.379 − 218 =
38. 38.888 − 439 =
39. 39.869 − 699 =
40. 40.905 − 409 =

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