Define four functions - add, subtract, multiply, divide that add multiply etc two numbers and return the result. Each should have two integer number arguments. The user is asked to input two numbers. These numbers will be passed as arguments into one of the functions. The user is asked to input 1 to add, 2 to subtract etc. If they input 1, call the ‘add’ function, input 2 calls the ‘subtract’ function etc. Output the returned result as part of a sentence.