<?php
$number = 0;
$result = 0;
$op = '';

$input = "53+6*2=";
$inputLength = strlen($input);

for ($i=0;$i<$inputLength;$i++){
	
	$char = substr($input,$i,1);
	if ($char == "*"||$char== "="||$char== "-"||$char== "+"){
		
		if ($op == "+"){
			$result+=$number;
		}
		elseif($op == "*"){
			$result*=$number;
					}
		elseif($op == "-"){
			$result-=$number;
		}
		elseif ($op == "="){
			
		}
		else{
			$result= $number;
					}
		
			echo "op[$op] result[$result] number[$number] char[$char] \n";
			$number = 0;
			$op = $char;
			
	}
	elseif (is_numeric($char)){
		$number=$number*10+$char;
	}

}