Performing Basic Mathematical Operations with Variables in Python

Updated: at 03:45 AM

Python is a popular, easy-to-learn programming language used for a wide range of applications from web development and scientific computing to machine learning and data analysis. One of the key aspects of Python is its support for performing mathematical computations and operations. In this comprehensive guide, we will explain how to carry out basic math with variables in Python using clear examples and sample code snippets.

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Overview of Variables in Python

Before we can perform math with variables, it is important to understand what variables are in Python.

Variables are containers that store values in a program. We can give a variable a descriptive name that represents or refers to the value it contains. Variables don’t have fixed types - we can store integers, floats, strings etc in a variable and we can change the value of a variable later in the program.

To define a variable in Python, we use the assignment operator =.

# Assign integer value to variable
num = 10

# Assign float value
price = 9.99

# Assign string
name = "John"

Variable names should follow PEP 8 naming conventions - they can contain letters, numbers and underscores but cannot start with a number.

Now that we have an overview of variables, let’s see how to use them for mathematical computations in Python.

Basic Mathematical Operators in Python

Python provides the following basic arithmetic operators that can be used to perform mathematical operations:

These operators work as you would expect and follow standard mathematical rules for precedence and associativity.

We can use variables representing numeric values in combination with these operators to execute math operations in Python.

# Addition
num1 = 10
num2 = 20
sum = num1 + num2
print(sum) # Prints 30

# Subtraction
diff = num2 - num1
print(diff) # Prints 10

# Multiplication
product = num1 * num2
print(product) # Prints 200

# Division
quotient = num2 / num1
print(quotient) # Prints 2.0

# Modulus
remainder = num2 % num1
print(remainder) # Prints 0

# Exponentiation
result = num1 ** 2
print(result) # Prints 100

# Floor division
floor_val = num2 // num1
print(floor_val) # Prints 2

Note that dividing two integers in Python 3 returns a float value. Older Python 2 automatically returned an integer result for division of two ints.

We can also chain multiple math operators together:

# Operator chaining
x = 2 + 3 * 4 - 8 / 2
print(x) # Prints 10.0

The order of operations is followed based on precedence.

Math Functions in Python

Beyond the basic math operators, Python includes a set of built-in math functions that enable more complex mathematical calculations. These functions are included in the math module.

To use the math module, we need to import it first:

import math

Some common math functions provided by the math module include:

Let’s see some examples:

import math

print(math.ceil(4.2)) # 5
print(math.floor(4.2)) # 4
print(math.sqrt(16)) # 4.0
print(math.pow(2, 3)) # 8.0
print(math.fabs(-4.2)) # 4.2
print(math.factorial(5)) # 120
print(math.cos(math.pi)) # -1.0
print(math.sin(math.pi/2)) # 1.0
print(math.tan(math.pi/4)) # 0.9999999999999999

We pass the arguments to these math functions which perform the required mathematical operation and return the result.

This allows us to compute more complex math in Python very easily.

Accepting User Input for Math Operations

In real programs, we often want to get input from the user for our variables rather than hardcoding values. The input() function allows us to accept user input in Python.

Here is an example that gets two numbers from the user and prints their sum:

num1 = input("Enter first number: ")
num2 = input("Enter second number: ")

num1 = float(num1)
num2 = float(num2)

# Convert input to floats

sum = num1 + num2

print("Sum:", sum)

Note that we have to explicitly convert the input to floats using float(). Input values are always read as strings, so we need to convert them to numbers before math operations.

We can make this cleaner by putting it in a function:

def add():
  num1 = float(input("Enter first number: "))
  num2 = float(input("Enter second number: "))

  sum = num1 + num2

  print("Sum:", sum)

add()

Now we can call this add() function whenever we need to get two numbers from user and print their sum.

This is a simple example, we can extend this to accept input for any mathematical operation and perform it.

Formatting Print Output

When printing math results, we may want to format the output in a particular way. For example, limiting to 2 decimal places or comma separation.

Python provides string formatting options that can be used to format numbers printed to console.

Some common ways to format numbers are:

import math

num = 4.55523
print(f"{num:.2f}") # 4.56

num2 = 1234
print(f"{num2:,}") # 1,234

num3 = math.pi
print(f"{num3:.4f}") # 3.1416

Where:

String formatting provides many flexible options for formatting math results printed to console.

Examples of Common Math Operations

Let’s go through some examples of common math tasks and operations in Python.

Calculate Area of Circle

radius = 5
area = math.pi * radius ** 2
print("Area of circle:", area)

Generate Random Number

We can use the random module to generate random numbers in Python.

import random

random_num = random.randint(1,10)
print(random_num)

This will print a random integer between 1 and 10.

Calculate Mean and Standard Deviation

The statistics module provides functions for common statistical calculations.

import statistics

values = [1, 4, 7, 3, 2]

mean = statistics.mean(values)
std_dev = statistics.stdev(values)

print("Mean:", mean)
print("Standard deviation:", std_dev)

Solve Quadratic Equation

Given a, b, c coefficients we can find roots of quadratic equation using:

import cmath

a = 1
b = 2
c = -3

root1 = (-b + cmath.sqrt(b**2 - 4*a*c)) / (2*a)
root2 = (-b - cmath.sqrt(b**2 - 4*a*c)) / (2*a)

print(root1, root2)

This prints the complex roots.

Generate Fibonacci Sequence

The Fibonacci sequence is a series of numbers where each number is the sum of the previous two.

We can generate n numbers of the sequence using:

def fibonacci(n):
  a, b = 0, 1

  for i in range(n):
    print(a, end=' ')

    a, b = b, a+b

fibonacci(10)

This recursively calculates and prints the first n Fibonacci numbers.

Calculate Factorial

To calculate the factorial of a number mathematically:

import math

num = 5

fact = math.factorial(num)
print(fact)

Or recursively implement the factorial function:

def factorial(x):
  if x == 1:
    return 1
  else:
    return x * factorial(x-1)

print(factorial(5))

Conclusion

In this comprehensive guide, we explored how to perform basic mathematical operations in Python using variables, operators, built-in math functions and by accepting user input. Key points covered include:

Python provides extensive support for mathematical and scientific computing. With its simple syntax and built-in math capabilities, Python is easy to use for basic and advanced math operations alike. The concepts covered here should give you a solid base for using Python for most mathematical programming needs.