The Grid dashboard item enables you to add a summary value (a total) calculated against displayed values of an individual column, and show the result under this column. Note that you can add any number of totals for each column. For example, you can obtain the number of column records, average or maximum value, etc.
1.Right click on the Amount (Sum) header
2.Click Add Total and select Sum
3.Right click on the Source heading
4.Click Add Total and select Count
5.Right click on the Amount to get Min Max and Average or to Remove the total