calculator.py

#This function adds two numbers
def add(x,y):
 return x + y
#This function subtracts two numbers
def subtract(x,y):
 return x-y
#This function multiplies two numbers
def multiply(x,y):
 return x*y
#This function divides two numbers
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
choice =int(input("Enter choice(1/2/3/4):"))
num1 =int(input("Enter first number:"))
num2 =int(input("Enter second number:"))
if choice ==1:
	print(num1,"+",num2,"=",add(num1,num2))
elif choice==2:
	print(num1,"-",num2,"=",subtract(num1,num2))
elif choice==3:
	print(num1,"*",num2,"=",multiply(num1,num2))
elif choice==4:
	print(num1,"-",num2,"=",subtract(num1,num2))
else:
	print("invalid output")