Here’s a basic calculator in Python that can perform addition, subtraction, multiplication, and division. It takes user input for two numbers and the operation.

# Basic Calculator

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!"
    else:
        return x / y

def calculator():
    print("Select operation:")
    print("1. Add")
    print("2. Subtract")
    print("3. Multiply")
    print("4. Divide")
    
    choice = input("Enter choice (1/2/3/4): ")
    
    num1 = float(input("Enter first number: "))
    num2 = float(input("Enter second number: "))
    
    if choice == '1':
        print(f"{num1} + {num2} = {add(num1, num2)}")
    elif choice == '2':
        print(f"{num1} - {num2} = {subtract(num1, num2)}")
    elif choice == '3':
        print(f"{num1} * {num2} = {multiply(num1, num2)}")
    elif choice == '4':
        print(f"{num1} / {num2} = {divide(num1, num2)}")
    else:
        print("Invalid input")

# Run the calculator
calculator()