Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 91 · 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. 1.750 − 658 =
2. 2.814 − 369 =
3. 3.588 − 419 =
4. 4.851 − 667 =
5. 5.884 − 598 =
6. 6.936 − 799 =
7. 7.406 − 249 =
8. 8.834 − 297 =
9. 9.972 − 677 =
10. 10.995 − 687 =
11. 11.754 − 699 =
12. 12.615 − 198 =
13. 13.519 − 198 =
14. 14.809 − 597 =
15. 15.894 − 648 =
16. 16.512 − 417 =
17. 17.976 − 538 =
18. 18.862 − 617 =
19. 19.448 − 347 =
20. 20.911 − 167 =
21. 21.425 − 399 =
22. 22.760 − 497 =
23. 23.739 − 339 =
24. 24.825 − 797 =
25. 25.743 − 197 =
26. 26.928 − 799 =
27. 27.850 − 797 =
28. 28.929 − 539 =
29. 29.815 − 797 =
30. 30.745 − 379 =
31. 31.853 − 128 =
32. 32.884 − 169 =
33. 33.923 − 457 =
34. 34.325 − 208 =
35. 35.971 − 117 =
36. 36.835 − 349 =
37. 37.877 − 697 =
38. 38.624 − 239 =
39. 39.891 − 597 =
40. 40.812 − 797 =

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