To show the sum of row, you'll need to add a new column 'Total' just like in your image. You can show the sum of particular columns in this.

• First add new <th>Total</th> in the thead

• Then add new column in columns while initializing dataTable

   {
     "targets": 0,
     "data": null,
     "render": function ( data, type, row, meta ) {
              return parseInt(row.column1,10) + parseInt(row.column2,10) + parseInt(row.column3,10);
     }
   }