Unable to obtain post data

Question

<?php
header("Content-type:text/html;charset=utf-8");

echo <<<'FROM'
< from action="" method="post">
Please enter an integer:
<input type="number" name="num">
<input type="submit" value ="Submit">

</from>
FROM;

echo isset($_POST['num']);

Answer 1

Got it, the form is written backwards

Answer 2

Does anyone know the reason?