Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 611 · 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. 1.941 − 699 =
2. 2.877 − 598 =
3. 3.579 − 198 =
4. 4.676 − 578 =
5. 5.460 − 297 =
6. 6.528 − 407 =
7. 7.721 − 538 =
8. 8.837 − 299 =
9. 9.734 − 489 =
10. 10.715 − 669 =
11. 11.736 − 629 =
12. 12.998 − 798 =
13. 13.378 − 308 =
14. 14.406 − 377 =
15. 15.508 − 398 =
16. 16.876 − 497 =
17. 17.956 − 798 =
18. 18.976 − 798 =
19. 19.644 − 277 =
20. 20.857 − 598 =
21. 21.727 − 199 =
22. 22.454 − 398 =
23. 23.851 − 197 =
24. 24.653 − 628 =
25. 25.939 − 479 =
26. 26.497 − 449 =
27. 27.376 − 128 =
28. 28.645 − 577 =
29. 29.793 − 297 =
30. 30.913 − 168 =
31. 31.775 − 379 =
32. 32.927 − 567 =
33. 33.685 − 497 =
34. 34.532 − 497 =
35. 35.746 − 697 =
36. 36.696 − 128 =
37. 37.753 − 499 =
38. 38.870 − 658 =
39. 39.799 − 259 =
40. 40.265 − 137 =

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