I want to use map method on array with callback to another function. Everything seems to be working fine, but at the end returning values are not affected. I don't know what seems to be the problem.

```
var arr=[4,5,3,2];

function multi (x,callback){
 return callback(x*2); 
}

function add(x){
// alert(x);   when I'm alerting "x" here, it's value is multiplied as it should be
return x+3;  

}
var final=arr.map(function(a){multi(a,add); return a;});
final; // returns same values as Array "arr"

```