How to create module in Node Js to implement functionality?

Module:-

The module is used to contain the set of functions to implement functionality that can be called under node js main file.

exports.functionname=  function(){

      return statements;

}

How to call module under node js main file.

var http = require('http');

var ref = require('./modulename');

http.createServer(function (req, res) {

  res.writeHead(200, {'Content-Type': 'text/html'});

  res.write("hello" + ref.methodame());

  res.end();

}).listen(8080);

console.log("Program started at localhost 8080");

Now I am explaining the example of  SiCalc.js:-

exports.sicalc=function()

{

   p=12000;

   r=2.2;

   t=2;

   si = (p*r*t)/100

   return si;

}

Code of module:-

var http = require('http');

var ref = require('./simodule');

http.createServer(function (req, res) {

 res.writeHead(200, {'Content-Type': 'text/html'});

 res.write("result is " + ref.sicalc());

 res.end();

}).listen(8080);

console.log("Program started at localhost 8080");

ASSIGNMENT OF NODE JS,

CREATE this program using the module:-

WAP to create a mark sheet using five different subjects with the following conditions?

1)  all subject marks should be 0 to 100?

2)  If only one subject mark is <33 then the student will supply.

3)  If all subject marks are>33 then the student pass and displays division with percentage?

4)  if the minimum of two subject marks is <33 then the student will fail.

5)  if the student is suppl and the mark is >28 then five bonus marks will be added then the student will pass by grace and grace subject name.

6) display distinction subject name

7) display suppl subject name