flash input text sorunu

var sayi1:Number = sayi1_txt.text;
var sayi2:Number = sayi2_txt.text;
sonuc_txt.text = sayi1 + sayi2;

var sayi1:int=0;
sayi1=Number(sayi1_txt.text);

var sayi2:int=0;
sayi2=Number(sayi2_txt.text);

islem_btn.addEventListener(MouseEvent.CLICK, islem);

function islem(e:MouseEvent){
	
	sonuc_mc.sonuc_txt.text=Number(sayi1_txt.text)+Number(sayi2_txt.text);
	}