At this point the syntax error you are most likely to make is an illegal variable name, like class and yield, which are keywords, or odd~job and US$, which contain illegal characters.
If you put a space in a variable name, Python thinks it is two operands without an operator:
>>> bad name = 5 SyntaxError: invalid syntax
For syntax errors, the error messages don’t help much. The most common messages are SyntaxError: invalid syntax and SyntaxError: invalid token, neither of which is very informative.
The runtime error you are most likely to make is a “use before def;” that is, trying to use a variable before you have assigned a value. This can happen if you spell a variable name wrong:
>>> principal = 327.68>>> interest = principle * rateNameError: name 'principle' is not defined
Variables names are case sensitive, so LaTeX is not the same as latex.
At this point the most likely cause of a semantic error is the order of operations. For example, to evaluate 
, you might be tempted to write
>>> 1.0 / 2.0 * pi
But the division happens first, so you would get π/2, which is not the same thing! There is no way for Python to know what you meant to write, so in this case you don’t get an error message; you just get the wrong answer.
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