# Prompt the User

**00:00**
Now it’s time to tackle the last to-dos that are here. You edit the `72`

and the `37`

as values for `temp_far`

and `temp_cel`

.

**00:09**
But actually, you want to prompt the user to input a number. So the value of `temp_far`

should be a call of the `input()`

function.

**00:19**
And for now, just add something like `"F:"`

. You can bother about making it nice in a moment. For now, let’s just use the `input()`

function to prompt the user and see if our code works as it is.

**00:32**
So when you run the module, then you’re prompted with `F:`

, you add a Fahrenheit number, and then you get an error.

**00:41**
Okay, let’s have a look at the error. It’s a `TypeError`

that says you have an unsupported operand type for `-`

between `str`

and `int`

in line 8, which is inside of the `convert_far_to_cel()`

function.

**00:58**
So if you have a look at line 8, then you have the expression `temp_far - 32`

.

**01:07**
Now coming back to the error again, it says that you are doing something with a `str`

and an `int`

. Maybe you know a little bit about the `input()`

function, and you already know why this error now occurs.

**01:20**
The reason for this is that `input()`

always returns a `str`

. So even if you added `72`

, which looks like a number, the return value from the `input()`

function will be a `str`

.

**01:33**
So you are trying to subtract the `int`

`32`

from the `str`

`"72"`

here, which obviously doesn’t work.

**01:44**
So what you need to do is you need to convert what the `input()`

function gives you back into a number value as well, and more specifically, into a `float`

.

**01:54**
So wrap both `input()`

function calls into a call to the built-in `float()`

function. So `temp_far = float()`

, and then the `input()`

call.

**02:06**
And now when you run the script, you can add in `72`

, and there is no error, but the error still occurs when you add something to the `"C:"`

because there you haven’t wrapped the `float()`

yet.

**02:18**
So let’s do this as well. `temp_cel = float()`

, and then the `input()`

call. And don’t forget to put a closing parenthesis at the end of the line.

**02:31**
And now when you run the module again and add `72`

for the Fahrenheit and `37`

for the Celsius, then the result is as expected. That’s good news. So with the `float()`

function call, you convert the input, which comes in as a `str`

, into a `float`

, and then all your calculations work.

**02:55**
You can remove the comment that stated the task.

**03:00**
Next, the only thing that’s left is making all those strings and input requests a bit more readable, so you have a nicer message there.

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