How to add amount field in advanced pdf template for item receipt?

Dear How To add amount field in advanced pdf template for item receipt,

i tried to multiply rate * quantity it didnt work throwing an error

later i have called this filed in code and try to multiply still throwing same error

<#if record.item?has_content>

<table cellspacing="2" border="1" class="itemtable" style="width: 100%; margin-top: 10px;"><!-- start items --><#list record.item as item><#if item_index==0><#assign qty_sum=0><#assign qty_mul=0><#assign qty_multotal=0>

<thead>

<tr>

   <th align="center" border-right="1" border-bottom="1" width="5%">S.NO</th>

   <th align="center" border-right="1" border-bottom="1" width="15%">Dispaly Name</th>

   <th align="center" border-right="1" border-bottom="1" width="20%">Description</th>