Tweening Numbers

I thought I read something about this here one time but a search didn’t bring up any results. What I want to do is tween a number from lets say 0 to 50 using the Tween class. The below is an example of my tween but it wasn’t working (NOTE i’m using TweenExtended but if you change the tween to Tween only it will be the same thing, i just have a habit of using the TweenExtended class):


import mx.transitions.easing.*;
import mx.transitions.TweenExtended;

var myNum:Number = 0;

var _tween:TweenExtended = new TweenExtended(myNum, ["myNum"], Regular.easeOut, [0], [50], 5, true);

_tween.onMotionChanged = function(obj) {
    trace(myNum);
};

any ideas?