## Eval-calculator

importance: 4

Create a calculator that prompts for an arithmetic expression and returns its result.

There’s no need to check the expression for correctness in this task.

Let’s use `eval`

to calculate the maths expression:

```
let expr = prompt("Type an arithmetic expression?", '2*3+2');
alert( eval(expr) );
```

The user can input any text or code though.

To make things safe, and limit it to arithmetics only, we can check the `expr`

using a regular expression, so that it only may contain digits and operators.