Floating point calculation problem

[Schizoid Man]

> raw_input() takes a line from the keyboard (handwave) and returns it
> as a string.
> 
> input() in 2.X takes a line from the keyboard and evaluates it as a
> Python expression.
> 
> float() takes a string, float, int, etc, and returns the
> nearest-equivalent floating point value.
> 
> What's the input you're giving to it?

Something simple like 3.0. 

PS - I'm new to Python, hence the newbie questions.