Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 364 · 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. 1.859 − 799 =
2. 2.730 − 597 =
3. 3.955 − 698 =
4. 4.371 − 299 =
5. 5.963 − 799 =
6. 6.514 − 298 =
7. 7.625 − 298 =
8. 8.714 − 598 =
9. 9.996 − 197 =
10. 10.853 − 697 =
11. 11.522 − 477 =
12. 12.914 − 679 =
13. 13.526 − 218 =
14. 14.426 − 198 =
15. 15.981 − 299 =
16. 16.217 − 167 =
17. 17.740 − 549 =
18. 18.855 − 609 =
19. 19.937 − 598 =
20. 20.898 − 797 =
21. 21.979 − 798 =
22. 22.728 − 418 =
23. 23.454 − 429 =
24. 24.986 − 497 =
25. 25.432 − 197 =
26. 26.962 − 798 =
27. 27.941 − 397 =
28. 28.849 − 398 =
29. 29.350 − 169 =
30. 30.850 − 697 =
31. 31.870 − 799 =
32. 32.533 − 397 =
33. 33.893 − 298 =
34. 34.878 − 499 =
35. 35.311 − 118 =
36. 36.520 − 298 =
37. 37.829 − 388 =
38. 38.794 − 557 =
39. 39.643 − 498 =
40. 40.947 − 799 =

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