Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 553 · 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. 1.942 − 699 =
2. 2.945 − 137 =
3. 3.624 − 599 =
4. 4.578 − 328 =
5. 5.961 − 698 =
6. 6.530 − 458 =
7. 7.917 − 697 =
8. 8.687 − 567 =
9. 9.576 − 198 =
10. 10.897 − 397 =
11. 11.862 − 797 =
12. 12.910 − 497 =
13. 13.793 − 327 =
14. 14.684 − 177 =
15. 15.445 − 427 =
16. 16.733 − 548 =
17. 17.901 − 547 =
18. 18.959 − 199 =
19. 19.496 − 297 =
20. 20.816 − 587 =
21. 21.905 − 699 =
22. 22.709 − 617 =
23. 23.815 − 568 =
24. 24.946 − 597 =
25. 25.917 − 798 =
26. 26.913 − 578 =
27. 27.791 − 697 =
28. 28.887 − 799 =
29. 29.877 − 597 =
30. 30.870 − 799 =
31. 31.705 − 189 =
32. 32.719 − 297 =
33. 33.538 − 507 =
34. 34.549 − 499 =
35. 35.809 − 698 =
36. 36.623 − 287 =
37. 37.646 − 249 =
38. 38.933 − 257 =
39. 39.529 − 449 =
40. 40.358 − 207 =

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