Here in this article, we have provided a python source code for a simple calculator that can perform basic arithmetic operations such as Addition, Multiplication, Division, subtraction, and modules.

**Prerequisite topics to create this program.**

- Python Input, Output
- Python Data types
- Python User-defined Functions
- Python Arithmetic Operators
- Python If…..elif statements.

**Steps**

- Create 4 different functions add(), sub(), mul(), and div(), for four different operaitons.
- First, ask the user to select the operation.
- Ask the user to enter two values for the operations.
- according to the user operator selection call the corresponding function.

**Python Program to Make a Simple Calculator**

**Code:**

def add(a, b): return a + b def sub(a, b): return a - b def mul(a, b): return a * b def div(a, b): return a / b print("Select the Operation.") print("Enter 1 for Additon") print("Enter 2 for Subtraction") print("Enter 3 for Multiplication") print("Enter 4 for Division") operation = input() num1 = float(input("Enter the First number: ")) num2 = float(input("Enter the Second number: ")) if operation == '1': print(num1,"+",num2,"=", add(num1,num2)) elif operation == '2': print(num1,"-",num2,"=", sub(num1,num2)) elif operation == '3': print(num1,"*",num2,"=", mul(num1,num2)) elif operation == '4': print(num1,"/",num2,"=", div(num1,num2)) else: print("Please Enter 1 or 2 or 3 or 4")

**Output 1:**

Select the Operation. Enter 1 for Addition Enter 2 for Subtraction Enter 3 for Multiplication Enter 4 for Division 4 Enter the First number: 12 Enter the Second number: 4 12.0 / 4.0 = 3.0

**Output 2:**

Select the Operation. Enter 1 for Addition Enter 2 for Subtraction Enter 3 for Multiplication Enter 4 for Division 2 Enter the First number: 23 Enter the Second number: 42 23.0 - 42.0 = -19.0