Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 893 · 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. 1.929 − 408 =
2. 2.464 − 167 =
3. 3.693 − 498 =
4. 4.774 − 189 =
5. 5.832 − 377 =
6. 6.902 − 797 =
7. 7.224 − 199 =
8. 8.872 − 497 =
9. 9.933 − 299 =
10. 10.742 − 697 =
11. 11.716 − 197 =
12. 12.963 − 128 =
13. 13.912 − 368 =
14. 14.384 − 198 =
15. 15.821 − 319 =
16. 16.205 − 137 =
17. 17.825 − 519 =
18. 18.788 − 598 =
19. 19.819 − 699 =
20. 20.730 − 699 =
21. 21.662 − 609 =
22. 22.923 − 298 =
23. 23.874 − 369 =
24. 24.519 − 298 =
25. 25.398 − 189 =
26. 26.778 − 698 =
27. 27.811 − 409 =
28. 28.655 − 598 =
29. 29.533 − 397 =
30. 30.746 − 629 =
31. 31.929 − 699 =
32. 32.867 − 497 =
33. 33.277 − 197 =
34. 34.982 − 297 =
35. 35.458 − 387 =
36. 36.736 − 598 =
37. 37.961 − 399 =
38. 38.714 − 699 =
39. 39.848 − 597 =
40. 40.981 − 799 =

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