How to sum value of column form row Excel with PHP office

Question

I have an Excel file that I want to upload it with Phpoffice, and preview on web application

everything works fine and success with this code:

if(isset($_POST['submit'])){
        $err ="";
        $ekstensi="";
        $success="";
        $file_name = $_FILES['filexls']['name'];
        $file_data = $_FILES['filexls']['tmp_name'];

        if (empty($file_name)) {

            $err .="<li>Silahkan masukan file.</li>";
            
        }else{
            $ekstensi = pathinfo($file_name)['extension'];
        }

        $ekstensi_allowed = array("xls","xlsx");
        if (!in_array($ekstensi,$ekstensi_allowed)) {

            $err .= "<li>Silahkan masukan file tipe xls, atau xlsx. File yang sekarang <b>$file_name</b>tipenya<b>$ekstensi</b></li>";
        }
      

<table class="table table-bordered">
              <thead>
                <tr>
                  
                  <th>NO</th>
                 
                  <th>UARAIAN PEKERJAAN</th>
                  <th>VOLUME</th>
                  <th class="tex-wrap">JUMLAH VOLUME</th>
                  <th>SATUAN</th>
                  <th>HARGA SATUAN</th>
                  <th>HARGA STANDARD</th>
                  <th>STATUS</th>
                  <th>JUMLAH</th>
                  <th>TAGUIHAN BULAN</th>
                  
              </tr>
              </thead>
              <tbody>
             <tr>

    <?php
            $no=0;
            if(empty($err)){
                $reader =\PhpOffice\PhpSpreadsheet\IOFactory::createReaderForFile($file_data);
                $spreadsheet = $reader->load($file_data);
                $sheetData = $spreadsheet->getActiveSheet()->toArray();
                
                $jumlahData=1;
                for ($i=1; $i<count($sheetData); $i++) {    
                        
                        $no = $sheetData[$i]['0'];
                        $urai = $sheetData[$i]['1'];
                        $volume = $sheetData[$i]['12'];
                        $jum_vol = $sheetData[$i]['14'];
                        $sat = $sheetData[$i]['15'];
                        $harga = $sheetData[$i]['16'];
                        $jum = $sheetData[$i]['17'];
                        ?>
                         <th><?=$no?></th>
                         <th><?=$urai?></th>
                         <th><?=$volume?></th>
                         <th><?=$jum_vol?></th>
                         <th><?=$sat?></th>
                         <th><?=$harga?></th>
                         <th><?=$jum?></th>
                     </tr>
            <?php
        }
    }?>

and this is the result result view

Now I want summarize the column form row "JUMLAH"($jum) which is the data that I want to sum just like this:

var_dump($jum);


 NULL string(6) "170500" NULL NULL NULL NULL string(5) "60720" string(5) "49784" string(5) "25000" string(5) "25000" string(6) "331004" NULL string(6) "300000" NULL NULL NULL NULL string(5) "14231" string(4) "5001" string(5) "25000" string(5) "25000" string(6) "369232" NULL

pleas give me some clue...thanks