Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 16 · 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. 1.739 − 498 =
2. 2.703 − 578 =
3. 3.637 − 497 =
4. 4.860 − 698 =
5. 5.327 − 227 =
6. 6.712 − 298 =
7. 7.930 − 697 =
8. 8.694 − 198 =
9. 9.867 − 697 =
10. 10.824 − 797 =
11. 11.971 − 289 =
12. 12.736 − 699 =
13. 13.549 − 438 =
14. 14.834 − 158 =
15. 15.961 − 799 =
16. 16.885 − 699 =
17. 17.709 − 397 =
18. 18.622 − 577 =
19. 19.950 − 797 =
20. 20.897 − 598 =
21. 21.654 − 499 =
22. 22.744 − 628 =
23. 23.738 − 657 =
24. 24.925 − 458 =
25. 25.746 − 398 =
26. 26.790 − 297 =
27. 27.399 − 298 =
28. 28.856 − 497 =
29. 29.709 − 688 =
30. 30.633 − 287 =
31. 31.890 − 527 =
32. 32.834 − 289 =
33. 33.242 − 178 =
34. 34.913 − 399 =
35. 35.794 − 199 =
36. 36.955 − 499 =
37. 37.939 − 499 =
38. 38.705 − 399 =
39. 39.997 − 697 =
40. 40.847 − 319 =

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