Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 622 · 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. 1.400 − 297 =
2. 2.940 − 198 =
3. 3.865 − 597 =
4. 4.753 − 698 =
5. 5.959 − 599 =
6. 6.537 − 398 =
7. 7.394 − 239 =
8. 8.941 − 297 =
9. 9.770 − 237 =
10. 10.844 − 669 =
11. 11.446 − 257 =
12. 12.937 − 399 =
13. 13.963 − 797 =
14. 14.882 − 398 =
15. 15.491 − 409 =
16. 16.963 − 798 =
17. 17.964 − 457 =
18. 18.839 − 598 =
19. 19.952 − 498 =
20. 20.883 − 497 =
21. 21.803 − 598 =
22. 22.920 − 298 =
23. 23.701 − 369 =
24. 24.954 − 799 =
25. 25.905 − 798 =
26. 26.869 − 447 =
27. 27.750 − 448 =
28. 28.916 − 298 =
29. 29.673 − 298 =
30. 30.352 − 259 =
31. 31.658 − 568 =
32. 32.758 − 667 =
33. 33.849 − 497 =
34. 34.768 − 308 =
35. 35.823 − 369 =
36. 36.532 − 299 =
37. 37.903 − 669 =
38. 38.674 − 199 =
39. 39.629 − 399 =
40. 40.497 − 327 =

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