Entity query - calculate the difference between income and expenses a

Question

Help me please!!!

 

I have:

public class Warehouse
{
public int WarehouseId { get; set; }
public DateTime? DateOperation { get; set; }// date record
public int Nomenclature { get; set; }// name
public int Operation { get; set; }// operation: only income and expense
public decimal Quantity { get; set; }
}
using (Cxt db = new Cxt())
{
gridQuery.DataSource = ???
}

i need to calculate the difference between income and expense and show everything in the table. I think the approach should be:

 

select all fields income, summarize, select all fields expenditure, summarize, subtract from the amounts of income the amount of expenditure and write in the table, and so on all fields of the nomenclature.