Как добавить кнопку paypal checkout в каждой строке таблицы

Решено!

<?php 
function evalmath($equation)
{
    $result = 0;
    // sanitize imput
    $equation = preg_replace("/[^a-z0-9+\-.*\/()%]/","",$equation);
    // convert alphabet to $variabel 
    $equation = preg_replace("/([a-z])+/i", "\$$0", $equation); 
    // convert percentages to decimal
    $equation = preg_replace("/([+-])([0-9]{1})(%)/","*(1\$1.0\$2)",$equation);
    $equation = preg_replace("/([+-])([0-9]+)(%)/","*(1\$1.\$2)",$equation);
    $equation = preg_replace("/([0-9]{1})(%)/",".0\$1",$equation);
    $equation = preg_replace("/([0-9]+)(%)/",".\$1",$equation);
    if ( $equation != "" ){
        $result = @eval("return " . $equation . ";" );
    }
    if ($result == null) {
        throw new Exception("Unable to calculate equation");
    }
    echo $result;
   // return $equation;
}


$a = 2;
$b = 3;
$c = 5;
$f1 = "a*b+c";

$f1 = str_replace("a", $a, $f1);
$f1 = str_replace("b", $b, $f1);
$f1 = str_replace("c", $c, $f1);

evalmath($f1);
/*if ( $equation != "" ){

    $result = @eval("return " . $equation . ";" );
}
if ($result == null) {

    throw new Exception("Unable to calculate equation");
}
echo $result;*/
?>