:A very simple definition of using '''functions''' is like having '''smaller programs contained inside a larger program''' that can be run by '''function name''' to perform '''repeated or commonly routine tasks'''. Usually, the function will contain programming code in some part of the main program (By calling the function by name to run code that is already stored in internal memory prevents the program from repeating the entry of repetitive code, thus reducing the size of the program and making it execute more efficiently. When creating programs that define and use functions, '''a large programming task can be broken-down into smaller elements''' (or '''modules'''). This is why creating programs that use functions is referred to as '''modular programming'''.