VBA Format Cells based on another sheet

Question

I am needing to add a variable range, per row starting in G2 (always) and carrying through the lastrow/lastcol -4 and then subtracting the value in the D column for each row & entering that result in lastcol-3. I've pieced this code together from other codes, and never used function.Sum, so I may be way off. Here is what I currently have for my code:

Answer 1

lastcol is a number not a letter and Range, when using strings, expects letters.

Change to Cells():

sht.Cells(i,lastcol-3).Value = Application.WorksheetFunction.Sum(sht.Range(sht.Cells(i,7),sht.Cells(i,lastcol-4)))