Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 963 · 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. 1.783 − 447 =
2. 2.185 − 128 =
3. 3.843 − 197 =
4. 4.859 − 797 =
5. 5.559 − 359 =
6. 6.823 − 377 =
7. 7.975 − 197 =
8. 8.643 − 299 =
9. 9.926 − 268 =
10. 10.846 − 697 =
11. 11.864 − 798 =
12. 12.885 − 799 =
13. 13.858 − 299 =
14. 14.846 − 197 =
15. 15.940 − 799 =
16. 16.225 − 169 =
17. 17.703 − 599 =
18. 18.897 − 798 =
19. 19.472 − 217 =
20. 20.530 − 398 =
21. 21.644 − 329 =
22. 22.951 − 337 =
23. 23.267 − 239 =
24. 24.816 − 799 =
25. 25.987 − 359 =
26. 26.888 − 459 =
27. 27.823 − 598 =
28. 28.966 − 499 =
29. 29.685 − 268 =
30. 30.825 − 699 =
31. 31.221 − 157 =
32. 32.414 − 197 =
33. 33.937 − 698 =
34. 34.231 − 197 =
35. 35.730 − 487 =
36. 36.891 − 488 =
37. 37.693 − 398 =
38. 38.837 − 598 =
39. 39.585 − 417 =
40. 40.838 − 269 =

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