Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 883 · 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. 1.619 − 198 =
2. 2.954 − 297 =
3. 3.765 − 197 =
4. 4.296 − 198 =
5. 5.836 − 648 =
6. 6.905 − 797 =
7. 7.571 − 337 =
8. 8.559 − 239 =
9. 9.504 − 199 =
10. 10.850 − 467 =
11. 11.884 − 499 =
12. 12.908 − 199 =
13. 13.854 − 259 =
14. 14.806 − 198 =
15. 15.999 − 698 =
16. 16.856 − 497 =
17. 17.767 − 557 =
18. 18.638 − 497 =
19. 19.648 − 157 =
20. 20.666 − 267 =
21. 21.869 − 237 =
22. 22.978 − 368 =
23. 23.827 − 549 =
24. 24.822 − 799 =
25. 25.627 − 478 =
26. 26.832 − 227 =
27. 27.895 − 397 =
28. 28.616 − 169 =
29. 29.902 − 298 =
30. 30.730 − 399 =
31. 31.940 − 619 =
32. 32.862 − 239 =
33. 33.834 − 797 =
34. 34.268 − 247 =
35. 35.863 − 599 =
36. 36.690 − 457 =
37. 37.773 − 597 =
38. 38.777 − 168 =
39. 39.484 − 399 =
40. 40.629 − 398 =

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