Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 966 · 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. 1.477 − 197 =
2. 2.869 − 798 =
3. 3.815 − 698 =
4. 4.927 − 399 =
5. 5.316 − 278 =
6. 6.233 − 198 =
7. 7.904 − 799 =
8. 8.595 − 477 =
9. 9.484 − 387 =
10. 10.647 − 398 =
11. 11.971 − 797 =
12. 12.865 − 188 =
13. 13.946 − 298 =
14. 14.509 − 349 =
15. 15.963 − 499 =
16. 16.938 − 637 =
17. 17.891 − 397 =
18. 18.692 − 297 =
19. 19.816 − 197 =
20. 20.418 − 188 =
21. 21.688 − 178 =
22. 22.869 − 397 =
23. 23.950 − 799 =
24. 24.643 − 418 =
25. 25.712 − 598 =
26. 26.987 − 498 =
27. 27.836 − 247 =
28. 28.816 − 498 =
29. 29.911 − 798 =
30. 30.563 − 348 =
31. 31.913 − 397 =
32. 32.261 − 237 =
33. 33.572 − 377 =
34. 34.603 − 297 =
35. 35.738 − 597 =
36. 36.773 − 698 =
37. 37.817 − 698 =
38. 38.521 − 498 =
39. 39.325 − 199 =
40. 40.703 − 257 =

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