Hello, Pin,

By default, RadGridView shows the summary row and the respective calculated value for each group when the group is expanded. However, for the collapsed state, the summary value is not shown.

There is no built-in mechanism to show the summary value for the collapsed group. However, I believe that the following knowledge base article will give you quite a good start for a solution that would perfectly fit your needs: https://www.telerik.com/support/kb/winforms/gridview/details/gridview-with-visible-summary-cells-in-a-collapsed-group

I hope this information helps. If you need any further assistance please don't hesitate to contact me. 

Regards,
Dess | Tech Support Engineer, Sr.
Progress Telerik