Activeadmin - Need to add two values and show it in third column
<p>I am trying to add the values and introduce a new column in Activeadmin, so that when I add the values it automatically sum up the values and show it in the next column.</p>

<p>Image for reference:<br>
<img src="https://i.stack.imgur.com/YKEJW.jpg" alt="image is here"></p>