Generally speaking a calculator answer is NOT exact, because the calculator must (usually) approximate a number. For example π is exact, but 3.1415926535897931 is not no matter how many decimals you carry. When asked for exact answers do NOT use your calculator! Here are some more examples:
| Exact | Not Exact |
| 0.66667 | |
| exp(4) | 54.59815 |
|
7.79422 |
|
| or 0.25 | - |