Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 930 · 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. 1.972 − 797 =
2. 2.430 − 198 =
3. 3.271 − 219 =
4. 4.684 − 189 =
5. 5.613 − 599 =
6. 6.743 − 698 =
7. 7.326 − 198 =
8. 8.921 − 487 =
9. 9.965 − 478 =
10. 10.566 − 298 =
11. 11.897 − 597 =
12. 12.657 − 598 =
13. 13.901 − 508 =
14. 14.962 − 467 =
15. 15.973 − 397 =
16. 16.993 − 797 =
17. 17.930 − 639 =
18. 18.922 − 598 =
19. 19.809 − 657 =
20. 20.415 − 198 =
21. 21.482 − 399 =
22. 22.336 − 218 =
23. 23.820 − 799 =
24. 24.916 − 419 =
25. 25.376 − 337 =
26. 26.830 − 599 =
27. 27.783 − 298 =
28. 28.878 − 298 =
29. 29.918 − 298 =
30. 30.550 − 397 =
31. 31.641 − 248 =
32. 32.842 − 799 =
33. 33.992 − 299 =
34. 34.242 − 228 =
35. 35.543 − 397 =
36. 36.991 − 597 =
37. 37.983 − 679 =
38. 38.870 − 587 =
39. 39.710 − 378 =
40. 40.939 − 698 =

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