If you are pasting this codes to a .php file, you need to add '<?php' before
these codes and '?>' after the codes : <?php echo ("Test") ; ?>

----------------------------------- Code 1 -----------------------------------
$var_1 = 123 ; // Number
echo ($var_1) ; // Print value of $var_1

----------------------------------- Code 2 -----------------------------------
$var_2 = "123" ; // String
echo ($var_2) ;

----------------------------------- Code 3 -----------------------------------
$var_3 = '123' ; // String
echo ($var_3) ;

----------------------------------- Code 4 -----------------------------------
$var_4 = array('123', '456', '789') ; // Array : the first element is '123'
print_r ($var_4) ; // Print all array elements

----------------------------------- Code 5 -----------------------------------
$var_5 = array("Name" => "Ali", "Address" => "Tehran") ; // Array
print_r ($var_5) ; // Print all array elements