var sayilar = [];
while(sayilar.length != 4)
sayilar.push(parseInt(prompt('sayi giriniz: ')));
var enbuyuk = (sayilar[0] > sayilar[1] && sayilar[0] > sayilar[2] && sayilar[0] > sayilar[3] ? sayilar[0] : sayilar[1] > sayilar[0] && sayilar[1] > sayilar[2] && sayilar[1] > sayilar[3] ? sayilar[1] : sayilar[2] > sayilar[0] && sayilar[2] > sayilar[1] && sayilar[2] > sayilar[3] ? sayilar[2] : sayilar[3]);
alert("en buyuk sayi: " + enbuyuk);

var dogum = prompt("dogum yiliniz: ");
var a = (new Date().getFullYear() - dogum);
alert('yasiniz: '+a);