Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 262 · 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. 1.389 − 308 =
2. 2.552 − 498 =
3. 3.748 − 569 =
4. 4.867 − 689 =
5. 5.725 − 699 =
6. 6.894 − 378 =
7. 7.765 − 299 =
8. 8.613 − 227 =
9. 9.901 − 699 =
10. 10.907 − 798 =
11. 11.531 − 189 =
12. 12.747 − 159 =
13. 13.906 − 597 =
14. 14.783 − 399 =
15. 15.592 − 369 =
16. 16.500 − 478 =
17. 17.721 − 698 =
18. 18.633 − 399 =
19. 19.585 − 338 =
20. 20.639 − 397 =
21. 21.812 − 597 =
22. 22.477 − 397 =
23. 23.970 − 697 =
24. 24.788 − 407 =
25. 25.583 − 359 =
26. 26.794 − 297 =
27. 27.398 − 178 =
28. 28.526 − 259 =
29. 29.879 − 527 =
30. 30.615 − 497 =
31. 31.975 − 307 =
32. 32.520 − 299 =
33. 33.562 − 528 =
34. 34.652 − 629 =
35. 35.268 − 197 =
36. 36.847 − 349 =
37. 37.891 − 798 =
38. 38.608 − 197 =
39. 39.640 − 599 =
40. 40.863 − 689 =

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