Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 408 · 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. 1.224 − 197 =
2. 2.744 − 698 =
3. 3.550 − 499 =
4. 4.648 − 599 =
5. 5.439 − 398 =
6. 6.849 − 599 =
7. 7.682 − 239 =
8. 8.844 − 199 =
9. 9.793 − 697 =
10. 10.645 − 139 =
11. 11.442 − 199 =
12. 12.728 − 399 =
13. 13.279 − 247 =
14. 14.723 − 439 =
15. 15.733 − 698 =
16. 16.774 − 499 =
17. 17.996 − 799 =
18. 18.261 − 218 =
19. 19.979 − 598 =
20. 20.828 − 798 =
21. 21.649 − 597 =
22. 22.986 − 198 =
23. 23.982 − 698 =
24. 24.442 − 398 =
25. 25.935 − 798 =
26. 26.549 − 427 =
27. 27.842 − 219 =
28. 28.341 − 268 =
29. 29.883 − 799 =
30. 30.642 − 128 =
31. 31.572 − 418 =
32. 32.930 − 547 =
33. 33.797 − 698 =
34. 34.772 − 379 =
35. 35.965 − 798 =
36. 36.682 − 138 =
37. 37.904 − 499 =
38. 38.992 − 297 =
39. 39.955 − 397 =
40. 40.819 − 329 =

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