Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 157 · 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. 1.886 − 697 =
2. 2.383 − 198 =
3. 3.848 − 309 =
4. 4.397 − 197 =
5. 5.966 − 499 =
6. 6.838 − 137 =
7. 7.997 − 488 =
8. 8.605 − 197 =
9. 9.950 − 467 =
10. 10.885 − 799 =
11. 11.652 − 597 =
12. 12.869 − 699 =
13. 13.993 − 597 =
14. 14.923 − 599 =
15. 15.923 − 797 =
16. 16.696 − 578 =
17. 17.841 − 599 =
18. 18.722 − 697 =
19. 19.958 − 629 =
20. 20.746 − 657 =
21. 21.770 − 468 =
22. 22.718 − 647 =
23. 23.891 − 548 =
24. 24.514 − 498 =
25. 25.240 − 117 =
26. 26.189 − 138 =
27. 27.937 − 608 =
28. 28.743 − 417 =
29. 29.821 − 699 =
30. 30.880 − 699 =
31. 31.333 − 119 =
32. 32.359 − 298 =
33. 33.899 − 539 =
34. 34.473 − 377 =
35. 35.923 − 658 =
36. 36.955 − 137 =
37. 37.830 − 598 =
38. 38.991 − 697 =
39. 39.501 − 398 =
40. 40.726 − 627 =

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