Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 276 · 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. 1.740 − 218 =
2. 2.654 − 399 =
3. 3.742 − 499 =
4. 4.376 − 199 =
5. 5.724 − 618 =
6. 6.667 − 197 =
7. 7.568 − 359 =
8. 8.986 − 699 =
9. 9.777 − 299 =
10. 10.971 − 298 =
11. 11.757 − 298 =
12. 12.888 − 607 =
13. 13.921 − 799 =
14. 14.804 − 498 =
15. 15.750 − 299 =
16. 16.792 − 517 =
17. 17.642 − 599 =
18. 18.923 − 369 =
19. 19.859 − 499 =
20. 20.783 − 499 =
21. 21.597 − 397 =
22. 22.527 − 327 =
23. 23.910 − 498 =
24. 24.896 − 339 =
25. 25.536 − 298 =
26. 26.748 − 299 =
27. 27.679 − 428 =
28. 28.781 − 699 =
29. 29.903 − 798 =
30. 30.352 − 197 =
31. 31.828 − 198 =
32. 32.589 − 498 =
33. 33.606 − 449 =
34. 34.869 − 157 =
35. 35.987 − 599 =
36. 36.665 − 549 =
37. 37.953 − 799 =
38. 38.432 − 407 =
39. 39.736 − 388 =
40. 40.967 − 249 =

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