<?php

 
 
$input = "22+2+45+56+55555555=";
 
 
 
 
for($i=0; $i <= strlen($input); $i++)
{
    $char = substr($input, $i, 1);
    if ($char == '*' || $char == '+' || $char == '-' || $char == "=" )
    {
		$pieces = explode($char, $input);
		if($char == '*'){
			$result = $pieces[0] * $pieces[1];
		}
			elseif($char == '+'){
			$result = $pieces[0] + $pieces[1];
		}
 		elseif($char == '-'){
			$result = $pieces[0] - $pieces[1];
		}
				elseif($char == '='){
 echo $result;
		}
	
 
    }
}