$re = '/(-?[\d?]+)([^=\d?])(-?[\d?]+)=(-?[\d?]+)/m';
$str = '1+1=?
123*45?=5?088
-5?*-1=5?
19--45=5?
??*??=302?
?*11=??
??*1=??
??+??=??
?33438-103326=410112';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php