def add(num1,num2):
    s=num1+num2
    return s
def sub(num1,num2):
    su=num1-num2
    return su
def mul(num1,num2):
    m=num1*num2
    return m
def div(num1,num2):
    d=num1/num2
    return d

#module:each python program is module  #.py

#package :collection of modules

