Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 138 · 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. 1.785 − 659 =
2. 2.962 − 698 =
3. 3.876 − 297 =
4. 4.691 − 588 =
5. 5.457 − 197 =
6. 6.361 − 197 =
7. 7.808 − 587 =
8. 8.218 − 197 =
9. 9.888 − 327 =
10. 10.894 − 669 =
11. 11.828 − 399 =
12. 12.763 − 667 =
13. 13.739 − 199 =
14. 14.997 − 698 =
15. 15.989 − 799 =
16. 16.994 − 697 =
17. 17.926 − 399 =
18. 18.900 − 558 =
19. 19.460 − 199 =
20. 20.825 − 697 =
21. 21.653 − 257 =
22. 22.725 − 678 =
23. 23.855 − 698 =
24. 24.638 − 589 =
25. 25.948 − 658 =
26. 26.823 − 799 =
27. 27.601 − 299 =
28. 28.844 − 598 =
29. 29.633 − 308 =
30. 30.668 − 597 =
31. 31.981 − 798 =
32. 32.903 − 597 =
33. 33.543 − 507 =
34. 34.898 − 498 =
35. 35.720 − 698 =
36. 36.707 − 497 =
37. 37.299 − 179 =
38. 38.510 − 298 =
39. 39.858 − 399 =
40. 40.346 − 199 =

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