Python Program to Make a Simple Calculator

In this example you will learn to create a simple calculator that can add, subtract, multiply or divide depending upon the input from the user.

Simple Calculator by Making Functions

# Add Function for addition
def add(x,y):
    return x+y

# Subtraction Function
def subtract(x,y):
    return x-y

# Multiplication Function
def multiply(x,y):
    return x*y

# Division Function
def divide(x,y):
    return x/y

print("Select operation.")
print("1.Add")
print("2.Subtract")
print("3.Multiply")
print("4.Divide")

# Take input from the user something like scanf in C language
check =input("Enter choice(1/2/3/4):")

num1 = int(input("Enter first number:"))
num2 = int(input("Enter second number:"))
    
if check=="1":
    print(num1," + ",num2," = ",add(num1,num2))

elif check=="2":
    print(num1," - ",num2," = ",subtract(num1,num2))

elif check=="3":
    print(num1," * ",num2," = ",multiply(num1,num2))

elif check=="4":
    print(num1," / ",num2," = ",divide(num1,num2))

else:
    print("Invalid Input")

Output

Select operation.
1.Add
2.Subtract
3.Multiply
4.Divide
Enter choice(1/2/3/4):1
Enter first number:7
Enter second number:2
7  +  2  =  9

In this program, we ask the user to choose the desired operation. Options 1, 2, 3 and 4 are valid. Two numbers are taken and an if...elif...else branching is used to execute a particular section. User-defined functions add(), subtract(), multiply() and divide() evaluate respective operations.