Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 412 · 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. 1.525 − 119 =
2. 2.993 − 138 =
3. 3.346 − 148 =
4. 4.886 − 197 =
5. 5.953 − 499 =
6. 6.912 − 798 =
7. 7.665 − 297 =
8. 8.547 − 397 =
9. 9.633 − 299 =
10. 10.948 − 698 =
11. 11.560 − 258 =
12. 12.536 − 438 =
13. 13.670 − 299 =
14. 14.628 − 599 =
15. 15.916 − 647 =
16. 16.907 − 699 =
17. 17.596 − 298 =
18. 18.993 − 697 =
19. 19.857 − 469 =
20. 20.946 − 797 =
21. 21.900 − 798 =
22. 22.719 − 678 =
23. 23.760 − 658 =
24. 24.428 − 399 =
25. 25.900 − 698 =
26. 26.950 − 167 =
27. 27.972 − 699 =
28. 28.721 − 498 =
29. 29.625 − 499 =
30. 30.514 − 329 =
31. 31.585 − 199 =
32. 32.398 − 127 =
33. 33.416 − 198 =
34. 34.606 − 298 =
35. 35.493 − 388 =
36. 36.911 − 298 =
37. 37.721 − 399 =
38. 38.905 − 299 =
39. 39.719 − 599 =
40. 40.760 − 697 =

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