calculator.py

def add(x, y):
    return x + y

def subtract(x, y):
    return x - y

def multiply(x, y):
    return x * y

def divide(x, y):
    if y == 0:
        return "Cannot divide by zero!"
    return x / y

if __name__ == "__main__":
    print("Select operation:")
    print("1.Add")
    print("2.Subtract")
    print("3.Multiply")
    print("4.Divide")

    print(add(3,5))