Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 584 · 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. 1.612 − 469 =
2. 2.976 − 399 =
3. 3.888 − 697 =
4. 4.978 − 597 =
5. 5.602 − 327 =
6. 6.867 − 469 =
7. 7.538 − 359 =
8. 8.340 − 198 =
9. 9.833 − 439 =
10. 10.915 − 297 =
11. 11.299 − 228 =
12. 12.686 − 509 =
13. 13.893 − 297 =
14. 14.597 − 497 =
15. 15.631 − 597 =
16. 16.700 − 629 =
17. 17.514 − 247 =
18. 18.677 − 497 =
19. 19.627 − 499 =
20. 20.586 − 347 =
21. 21.462 − 409 =
22. 22.977 − 658 =
23. 23.553 − 497 =
24. 24.566 − 297 =
25. 25.899 − 417 =
26. 26.643 − 489 =
27. 27.908 − 697 =
28. 28.515 − 299 =
29. 29.803 − 529 =
30. 30.349 − 297 =
31. 31.344 − 259 =
32. 32.837 − 399 =
33. 33.691 − 497 =
34. 34.547 − 439 =
35. 35.366 − 298 =
36. 36.782 − 699 =
37. 37.810 − 448 =
38. 38.641 − 499 =
39. 39.735 − 298 =
40. 40.855 − 199 =

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