Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 261 · 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. 1.788 − 497 =
2. 2.609 − 469 =
3. 3.930 − 379 =
4. 4.692 − 538 =
5. 5.673 − 599 =
6. 6.569 − 327 =
7. 7.610 − 538 =
8. 8.813 − 798 =
9. 9.821 − 367 =
10. 10.538 − 428 =
11. 11.829 − 698 =
12. 12.961 − 587 =
13. 13.774 − 527 =
14. 14.773 − 299 =
15. 15.345 − 329 =
16. 16.909 − 399 =
17. 17.581 − 289 =
18. 18.874 − 499 =
19. 19.470 − 199 =
20. 20.693 − 599 =
21. 21.309 − 167 =
22. 22.765 − 697 =
23. 23.892 − 649 =
24. 24.933 − 799 =
25. 25.895 − 597 =
26. 26.587 − 179 =
27. 27.621 − 587 =
28. 28.941 − 357 =
29. 29.492 − 259 =
30. 30.560 − 428 =
31. 31.679 − 599 =
32. 32.491 − 199 =
33. 33.523 − 329 =
34. 34.341 − 199 =
35. 35.832 − 598 =
36. 36.834 − 167 =
37. 37.776 − 699 =
38. 38.711 − 599 =
39. 39.247 − 199 =
40. 40.729 − 308 =

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