In this tutorial, you'll learn how to use numbers in Python programs. We'll focus on integers and floats, the two most common numeric types used by beginners.
Integers
An integer is a whole number (positive or negative), such as:
-3, -1, 0, 1, 2, 100
In Python, the type of an integer is int
.
You can use basic mathematical operators to work with integers:
x = 20
y = 10
# Addition
total = x + y
print(total) # 30
# Subtraction
difference = x - y
print(difference) # 10
# Multiplication
product = x * y
print(product) # 200
# Division
quotient = x / y
print(quotient) # 2.0
Exponentiation
Use **
to calculate exponents:
x = 3
y = 3
power = x ** y
print(power) # 27
Order of Operations
Use parentheses ()
to control the order of evaluation:
result = 20 / (10 + 10)
print(result) # 1.0
Floats
A float is a number that has a decimal point:
0.5, 3.14, -2.75
The term "float" means that the decimal point can appear anywhere in the number.
You can use floats just like integers:
x = 0.5
y = 0.25
total = x + y
print(total) # 0.75
difference = x - y
print(difference) # 0.25
product = x * y
print(product) # 0.125
quotient = x / y
print(quotient) # 2.0
Division Always Returns a Float
Even when dividing two integers:
x = 20
y = 10
quotient = x / y
print(quotient) # 2.0
Mixing Types
If you mix an integer and a float, the result will always be a float:
x = 1
y = 2.0
total = x + y
print(total) # 3.0
Floating-Point Precision
Due to how computers store float values, sometimes results aren't exact:
x = 0.1
y = 0.2
total = x + y
print(total) # 0.30000000000000004
This is normal and expected in most programming languages.
Underscores in Numbers
For readability, you can use underscores in large numbers:
# Without underscores
count = 10000000000
# With underscores
count = 10_000_000_000
print(count) # 10000000000
Python ignores the underscores when storing and displaying the values. This also works with floats:
pi = 3.141_592_653
print(pi) # 3.141592653
Underscores in numbers were introduced in Python 3.6.
Exercises
Exercise 1
Create two integer variables, add them, subtract them, multiply them, and divide them.
a = 15
b = 5
print("Addition:", a + b)
print("Subtraction:", a - b)
print("Multiplication:", a * b)
print("Division:", a / b)
Exercise 2
Calculate 4 to the power of 3 using the exponentiation operator.
print(4 ** 3)
Exercise 3
Use parentheses to calculate this expression: 100 - 5 * (2 + 3)
.
result = 100 - 5 * (2 + 3)
print(result)
Exercise 4
Create two float variables and perform all four arithmetic operations.
x = 1.5
y = 0.5
print(x + y)
print(x - y)
print(x * y)
print(x / y)
Exercise 5
Create a large number using underscores for readability.
population = 8_000_000_000
print(population)
Summary
-
Python supports integers (
int
) and floats (float
). -
Use
+
,-
,*
,/
, and**
to perform arithmetic. -
Division always returns a float.
-
Mixing
int
andfloat
results in a float. -
Be aware of floating-point precision issues.
-
Use underscores
_
to format large numbers. -
Practice regularly to understand how numeric operations behave in different scenarios.
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