Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 419 · 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. 1.960 − 177 =
2. 2.905 − 499 =
3. 3.997 − 398 =
4. 4.334 − 177 =
5. 5.871 − 799 =
6. 6.915 − 617 =
7. 7.576 − 197 =
8. 8.694 − 497 =
9. 9.640 − 497 =
10. 10.998 − 559 =
11. 11.522 − 399 =
12. 12.851 − 699 =
13. 13.951 − 487 =
14. 14.773 − 309 =
15. 15.646 − 298 =
16. 16.990 − 419 =
17. 17.894 − 397 =
18. 18.730 − 397 =
19. 19.443 − 298 =
20. 20.765 − 697 =
21. 21.645 − 578 =
22. 22.879 − 599 =
23. 23.255 − 199 =
24. 24.446 − 229 =
25. 25.810 − 598 =
26. 26.645 − 519 =
27. 27.439 − 137 =
28. 28.606 − 277 =
29. 29.995 − 499 =
30. 30.799 − 329 =
31. 31.747 − 247 =
32. 32.345 − 239 =
33. 33.904 − 629 =
34. 34.403 − 299 =
35. 35.329 − 299 =
36. 36.957 − 488 =
37. 37.827 − 198 =
38. 38.243 − 199 =
39. 39.839 − 199 =
40. 40.673 − 357 =

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