How to insert a variable in a database which is calculated by 3 form fields

[ORB30]

Hello all

Im having an issue trying to insert a variable in to a database.
This variable is the math result of 3 fields of the form, a division multiplied by a number.

So far is returning always 0 so i thought you might gime me a hand here

This is the cold below :

// declare variables to be inserted
$venzini_kinisis_1 = ($_REQUEST['15']/$_REQUEST['8']) * $_REQUEST['1'];
$venzini_100ara = ($_REQUEST['16']/$_REQUEST['9']) * $_REQUEST['2'];
$venzini_super_1 = ($_REQUEST['17']/$_REQUEST['10']) * $_REQUEST['3'];
$venzini_95_1 = ($_REQUEST['18']/$_REQUEST['11']) * $_REQUEST['4'];
$venzini_95_2 = ($_REQUEST['19']/$_REQUEST['12']) * $_REQUEST['5'];
$venzini_super_2 = ($_REQUEST['20']/$_REQUEST['13']) * $_REQUEST['6'];
$venzini_kinisis_2 = ($_REQUEST['21']/$_REQUEST['14']) * $_REQUEST['7'];

if ((isset($_POST["MM_insert"])) && ($_POST["MM_insert"] == "insert_form")) {
$insertSQL = sprintf("INSERT INTO kiniseis (polisi_kinisis_1, polisi_100aras, polisi_super_1, polisi_95_1, polisi_95_2, polisi_super_2, polisi_kinisis_2) VALUES (%s, %s, %s, %s, %s, %s, %s)",

GetSQLValueString($_POST['".$venzini_kinisis_1"'], "double"),
GetSQLValueString($_POST['".$venzini_100ara"'], "double"),
GetSQLValueString($_POST['".$venzini_super_1"'], "double"),
GetSQLValueString($_POST['".$venzini_95_1"'], "double"),
GetSQLValueString($_POST['".$venzini_95_2"'], "double"),
GetSQLValueString($_POST['".$venzini_super_2"'], "double"),
GetSQLValueString($_POST['".$venzini_kinisis_2"'], "double"));

Thanks in advance :)

[BOMEz]

Are you sure that at no point in time one of your variables which is a denominators is a 0? If it is then it could cause you to get 0.

Try simply echoing all of the variables to actually see what their values are

[ORB30]

i use @ to avoid that thing :) so not to receive a notice from php "division by zero" i will echo and get back to see what is happening