index.html
<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="UTF8">
<title>JavaScriptの勉強</title>
</head>
<body>
<h1>JavaScriptの勉強</h1>
<script>
// javaScriptオブジェクト(Math)
// var m = new Math(();
// プロパティ
console.log(Math.PI);
console.log(Math.SQRT2);
// メソッド
var x = 5.238;
console.log(Math.floor(x));
console.log(Math.ceil(x));
console.log(Math.round(x));
console.log(Math.random());
</script>
</body>
</html>