Learning objectives
By the end of this section you should be able to
 Use arithmetic operators to perform calculations.
 Explain the precedence of arithmetic operators.
Numeric data types
Python supports two basic number formats, integer and floatingpoint. An integer represents a whole number, and a floatingpoint format represents a decimal number. The format a language uses to represent data is called a data type. In addition to integer and floatingpoint types, programming languages typically have a string type for representing text.
Concepts in Practice
Integers, floats, and strings
Assume that x = 1
, y = 2.0
, and s = "32"
.
Basic arithmetic
Arithmetic operators are used to perform mathematical operations like addition, subtraction, multiplication, and division.
Four basic arithmetic operators exist in Python:
 Addition (+)
 Subtraction ()
 Multiplication (*)
 Division (/)
Concepts in Practice
Applying arithmetic operators
Assume that x = 7
, y = 20
, and z = 2
.
Operator precedence
When a calculation has multiple operators, each operator is evaluated in order of precedence. Ex: 1 + 2 * 3
is 7
because multiplication takes precedence over addition. However, (1 + 2) * 3
is 9
because parentheses take precedence over multiplication.
Operator  Description  Example  Result 


Parentheses 



Exponentiation 



Positive, negative 



Multiplication, division 



Addition, subtraction 


Concepts in Practice
Multiple arithmetic operators
Try It
Values and types
Write a Python computer program that:
 Defines an integer variable named
'int_a'
and assigns'int_a'
with the value10
.  Defines a floatingpoint variable named
'float_a'
and assigns'float_a'
with the value10.0
.  Defines a string variable named
'string_a'
and assigns'string_a'
with the string value"10"
.  Prints the value of each of the three variables along with their type.
Try It
Meters to feet
Write a Python computer program that:
 Assigns the integer value
10
to a variable,meters
.  Assigns the floatingpoint value
3.28
to a variable,meter2feet
.  Calculates 10 meters in feet by multiplying
meter
bymeter2feet
. Store the result in a variable,feet
.  Prints the content of variable
feet
in the output.