vuthaihoc

<?php 
header('Content-Type: text/html; charset=utf-8');
$value1 = isset($_POST['value1']) ? $_POST['value1'] : '';
$value2 = isset($_POST['value2']) ? $_POST['value2'] : '';
$result = 0;
$msg = "";
if(isset($_POST)){
	if(is_numeric($value1) && is_numeric($value2)){
		if(isset($_POST['add'])){
			$result = $value1 + $value2;