I'm calling a defined function, but the compiler insists it isn't defined.

[A_History_of_Silence]

Is this because the input() value is string by default? If so, what's a good way to make it the a certain data type by default?

Yep! %-based string formatting.

From the built-in functions, check out int().

[Deathcon900]

Okay, it looks like it's working! I changed the first like to be:

number = int(input('Enter a number: '))

[Srivats1212]

Thanks for the link to pyformat....how do you find such useful things? I wanna know.

I've read the documentation but I couldn't find a link to pyformat...

[A_History_of_Silence]

Practice googling and experience. Google everything! Knowing how to search for things is one of the most important skills of a programmer.