Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 725 · 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. 1.413 − 398 =
2. 2.855 − 299 =
3. 3.864 − 168 =
4. 4.819 − 479 =
5. 5.863 − 798 =
6. 6.942 − 399 =
7. 7.998 − 527 =
8. 8.638 − 599 =
9. 9.877 − 797 =
10. 10.351 − 278 =
11. 11.316 − 228 =
12. 12.784 − 397 =
13. 13.840 − 638 =
14. 14.539 − 299 =
15. 15.661 − 549 =
16. 16.954 − 177 =
17. 17.750 − 498 =
18. 18.966 − 399 =
19. 19.994 − 277 =
20. 20.543 − 397 =
21. 21.498 − 199 =
22. 22.985 − 199 =
23. 23.755 − 628 =
24. 24.875 − 399 =
25. 25.659 − 199 =
26. 26.548 − 499 =
27. 27.967 − 557 =
28. 28.518 − 469 =
29. 29.472 − 379 =
30. 30.989 − 799 =
31. 31.767 − 699 =
32. 32.859 − 369 =
33. 33.942 − 657 =
34. 34.808 − 598 =
35. 35.866 − 298 =
36. 36.224 − 199 =
37. 37.892 − 648 =
38. 38.719 − 589 =
39. 39.677 − 598 =
40. 40.867 − 647 =

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