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Numbers

The interpreter acts as a simple calculator: you can type an expression at it and it will write the value. Expression syntax is straightforward: the operators + , - , * and / work just like in most other languages (for example, Pascal or C); parentheses ( () ) can be used for grouping. For example:

 >>> 2 + 2 
 4 
 >>> 50 - 5*6 
 20 
 >>> (50 - 5*6) / 4 
 5.0 
 >>> 8 / 5  # division always returns a floating point number 
 1.6

The integer numbers (e.g. 2 , 4 , 20 ) have type int , the ones with a fractional part (e.g. 5.0 , 1.6 ) have type float . We will see more about numeric types later in the tutorial.

Division ( / ) always returns a float . To do floor division and get an integer result (discarding any fractional result) you can use the // operator; to calculate the remainder you can use % :

 >>> 17 / 3  # classic division returns a float 
 5.666666666666667 
 >>>
>>> 17 // 3  # floor division discards the fractional part 
 5 
 >>> 17 % 3  # the % operator returns the remainder of the division 
 2 
 >>> 5 * 3 + 2  # result * divisor + remainder 
 17

With Python, it is possible to use the ** operator to calculate powers:

 >>> 5 ** 2  # 5 squared 
 25 
 >>> 2 ** 7  # 2 to the power of 7 
 128

etc.