Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 174 · 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. 1.762 − 599 =
2. 2.611 − 259 =
3. 3.694 − 669 =
4. 4.867 − 477 =
5. 5.676 − 299 =
6. 6.850 − 499 =
7. 7.673 − 598 =
8. 8.676 − 529 =
9. 9.739 − 498 =
10. 10.466 − 369 =
11. 11.570 − 409 =
12. 12.381 − 197 =
13. 13.628 − 359 =
14. 14.674 − 597 =
15. 15.793 − 197 =
16. 16.515 − 378 =
17. 17.449 − 238 =
18. 18.737 − 697 =
19. 19.799 − 548 =
20. 20.652 − 508 =
21. 21.999 − 799 =
22. 22.774 − 478 =
23. 23.647 − 539 =
24. 24.916 − 799 =
25. 25.961 − 498 =
26. 26.971 − 499 =
27. 27.929 − 699 =
28. 28.784 − 599 =
29. 29.686 − 259 =
30. 30.863 − 598 =
31. 31.708 − 608 =
32. 32.939 − 299 =
33. 33.638 − 597 =
34. 34.472 − 199 =
35. 35.326 − 199 =
36. 36.711 − 298 =
37. 37.708 − 647 =
38. 38.615 − 498 =
39. 39.345 − 308 =
40. 40.197 − 127 =

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