Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 698 · 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. 1.813 − 209 =
2. 2.607 − 469 =
3. 3.687 − 177 =
4. 4.843 − 698 =
5. 5.720 − 697 =
6. 6.871 − 498 =
7. 7.739 − 228 =
8. 8.657 − 379 =
9. 9.920 − 419 =
10. 10.927 − 648 =
11. 11.792 − 269 =
12. 12.531 − 498 =
13. 13.983 − 259 =
14. 14.221 − 199 =
15. 15.896 − 688 =
16. 16.845 − 199 =
17. 17.522 − 297 =
18. 18.733 − 409 =
19. 19.587 − 289 =
20. 20.851 − 799 =
21. 21.976 − 317 =
22. 22.847 − 429 =
23. 23.252 − 137 =
24. 24.401 − 298 =
25. 25.588 − 497 =
26. 26.958 − 308 =
27. 27.507 − 399 =
28. 28.805 − 399 =
29. 29.607 − 297 =
30. 30.844 − 618 =
31. 31.782 − 519 =
32. 32.832 − 299 =
33. 33.897 − 389 =
34. 34.913 − 128 =
35. 35.821 − 199 =
36. 36.969 − 279 =
37. 37.874 − 418 =
38. 38.841 − 318 =
39. 39.443 − 199 =
40. 40.827 − 479 =

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