By default, RadGrid can populate the aggregates of each column only in its footer cell as described in the Aggregates article.
In case the aggregates are crucial for the users you may consider using the StaticHeaders functionality. That way you can define a fixed height of the Grid so that the footer (with the aggregates) and the header are always visible and let the user scroll just the data items between the header and footer. You can test the StaticHeaders in the following live demo:
An alternative option could be to use some custom JavaScrpt logic to get the values from the footer cells and populate them in other elements inside or outside the RadGrid.
For example, you can use GridTemplateColumns and define HeaderTemplates with some container elements to be used to display the footer values inside the header. I have attached a sample project with one column header to serve as an idea (add the Telerik.Web.UI.dll in the bin folder to be able to run the sample).
I hope you will find this information helpful.
Please let me know if you have further questions.
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