Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 221 · 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. 1.760 − 697 =
2. 2.919 − 698 =
3. 3.690 − 299 =
4. 4.271 − 148 =
5. 5.814 − 639 =
6. 6.969 − 797 =
7. 7.970 − 179 =
8. 8.762 − 699 =
9. 9.925 − 397 =
10. 10.718 − 498 =
11. 11.459 − 267 =
12. 12.923 − 197 =
13. 13.739 − 659 =
14. 14.898 − 497 =
15. 15.873 − 299 =
16. 16.820 − 399 =
17. 17.996 − 499 =
18. 18.586 − 248 =
19. 19.622 − 227 =
20. 20.928 − 427 =
21. 21.624 − 127 =
22. 22.883 − 478 =
23. 23.749 − 397 =
24. 24.728 − 657 =
25. 25.762 − 679 =
26. 26.793 − 549 =
27. 27.747 − 639 =
28. 28.665 − 199 =
29. 29.986 − 799 =
30. 30.954 − 699 =
31. 31.954 − 587 =
32. 32.438 − 167 =
33. 33.635 − 599 =
34. 34.886 − 598 =
35. 35.871 − 798 =
36. 36.776 − 599 =
37. 37.851 − 699 =
38. 38.892 − 407 =
39. 39.667 − 299 =
40. 40.873 − 798 =

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