A Function is the simple callable object in python. A function can accept some arguments and possibly return some object. The following python code represents the basic calculator operation like addition, subtraction, multiplication and division. The code is well organized with different functions.

def menu(): #print what options you have print "Welcome to calculator in Python" print "your options are:" print " " print "1) Addition" print "2) Subtraction" print "3) Multiplication" print "4) Division" print "5) Quit calculator" print " " return input ("Choose your option: ")

def add(a,b): print a, "+", b, "=", a + b

def sub(a,b): print b, "-", a, "=", b - a

def mul(a,b): print a, "*", b, "=", a * b

def div(a,b): print a, "/", b, "=", a / b

loop = 1 choice = 0 while loop == 1: choice = menu() if choice == 1: add(input("Add this: "),input("to this: ")) elif choice == 2: sub(input("Subtract this: "),input("from this: ")) elif choice == 3: mul(input("Multiply this: "),input("by this: ")) elif choice == 4: div(input("Divide this: "),input("by this: ")) elif choice == 5: loop = 0

print "Thankyou for using calculator!"

OUTPUT:

Welcome to calculator in Python your options are:

1. Addition
2. Subtraction
3. Multiplication
4. Division
5. Quit calculator

Choose your option: 1 Add this: 25 to this: 35 25 + 35 = 60 Welcome to calculator your options are:

1. Addition
2. Subtraction
3. Multiplication
4. Division
5. Quit calculator

Choose your option: 3 Multiply this: 15 by this: 10 15 * 10 = 150 Welcome to calculator your options are:

1. Addition
2. Subtraction
3. Multiplication
4. Division
5. Quit calculator

Choose your option: 5 Thankyou for using calculator!