```
a = input('hour')
b = input('number of hours')
int(a)
int(b)
h = a // 24
s = a % 24
print(h, s)
a = a + s
print( 'hour now', a)
```
```
TypeError: unsupported operand type(s) for //: 'str' and 'int' on line 5
```
On line 5 we are trying to use integer division on `a` and `24`. The error message tells you that you are trying to divide a string by a number. In this case you know that `24` is a number so `a` must be a string. But how? You can see the function call on line 3 where you are converting `a` to an integer with `int(a)`. The problem is that the expression `int(a)` does not assign `a` to the integer. The proper assignment expression here is `a = int(a)`.

TypeError Example

TypeErrors occur when you try to combine two objects that are not compatible. For example you try to add together an integer and a string. Usually type errors can be isolated to lines that are using mathematical operators, and usually the line number given by the error message is an accurate indication of the line.

Rutgers University

Many problems in your program will lead to an error message.

Most common error messages:
- SyntaxError
- TypeError
- NameError
- ValueError

Less common error messages:
- AttributeError
- TimeLimitError
- IndexError
- IndentationError
- ExternalError
- UnboundLocalError
- ImportError
- ZeroDivisionError
- KeyError
- IOError

Error Messages

https://runestone.academy/runestone/books/published/fopp/index.html

Runestone: Foundations of Python Programming

Syntax errors happen when you make an error in the syntax of your program. Syntax errors are like making grammatical errors in writing.

Usually SyntaxErrors can be traced back to missing punctuation characters, such as parentheses, quotation marks, or commas.

SyntaxError

TypeError

Name errors almost always mean that you have used a variable before it has a value. Often NameErrors are simply caused by typos in your code. Other times you may simply mis-remember the name of a variable or even a function you want to call.

NameError

Value errors occur when you pass a parameter to a function and the function is expecting a certain limitations on the values, and the value passed is not compatible. 

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