Hi,

You can use MIN and MAX functions in the LINQ query to get the Minimum and Maximum value for each group. i.e:-

Code:
MaxValue = Max(CDec(ItemValue)), MinValue = Min(CDec(ItemValue))
As to other calculations you need doing, these all need to be Aggregate functions due to the fact that you are working within Groups of Items.

Hope that helps.

Cheers,

Ian