var sayi=7.5;
Math.ceil(sayi);//7
var sayi=17.5;
Math.floor(sayi);//17
var sayi=14.5;
Math.round(sayi);//15
<!DOCTYPE HTML>
<html lang="en-US">
<head>
<meta charset="UTF-8">
<title>UstaDerslik</title>
<script type="text/javascript">
var sayi1=5.68;
var sayi2=1.10;
var sayi3=7.50;
function yuvarla(){
document.getElementById("sayi1").innerHTML=sayi1+"="+Math.ceil(sayi1)+"-ceil";
document.getElementById("sayi2").innerHTML=sayi2+"="+Math.floor(sayi2)+"-floor";
document.getElementById("sayi3").innerHTML=sayi3+"="+Math.floor(sayi3)+"-floor";
document.getElementById("sayi4").innerHTML=sayi3+"="+Math.round(sayi3)+"-round";
}
</script>
</head>
<body>
<div id="sayi1"></div>
<div id="sayi2"></div>
<div id="sayi3"></div>
<div id="sayi4"></div>
<button onClick="yuvarla()">Yuvarla</button>
</body>
</html>