how to use variable with php code example

Example 1: php variables

<?php
  $string = 'string';
  $number = 1;
?>

Example 2: php variables

<?php
/* In PHP, a variable starts with the $ sign, 
followed by the name of the variable:
*/

$txt = "Hello world!";
$x = 5;
$y = 10.5;
?>