Gives the following error:
Can't convert 'int' object to str implicitly
and strangely the order matters
unsupported operand type(s) for +: 'int' and 'str'
Exactly why they are different in the way that they are is not what's important right now. What's important is that you're trying to combine different types and python doesn't know how to do that without help.
Brief List of Python Types
int - whole numbers for counting
float - decimal point numbers
str - strings of text
bool - boolean True or False
There are more but this short list will get you started.