Average on variable columns

[KANAN14]

I am looking for a macro to calculate an average of price, but the problem is that the number of columns is variable.

So basically we need the averaging is done in column G, every 2 columns (I & G & K...) and that until the end of the table. Is this possible? How?

[void]

Have you any title to your columns, if so, what are they? Can we find common elements in columns to take into account different from those not taken into account? Example: Tot_A_2008 / Tot_A_2009 / Tot_B_2008 / Tot_B_2009 / ...

From Macro:

Dim DerCol as long, c as long, MySom as long, MyNb as long, MyAvg
 
DerCol = sheets("File1").cells(1,rows(1).cells.count).end(xltoleft).column
For c = 7 to DerCol step 2 
     MySom = MySom + cells(2,c) 
     MyNb = MyNb +1 
Next c 
MyAvg = MySom /MyNb

[KANAN14]

I can not understand what you have done. Can you explain me or help me for easy understanding? I mean a simpler solution with an easy explanation would do the trick.

[void]

OK, try it, the comments are quite explicit to explain things.

Sub Avg()
 
Dim DerCol As Long, c As Long, MySom As Long, MyNb As Long, MyAvg
As Long, r As Long
 
DerCol = Sheets("File1").Cells(2, Rows(2).Cells.Count).End(xlToLeft).Column 'retrieves the last column filled on the basis of line 2
 
For r = 3 To 22 'Loop on the lines whereas the number is fixed
    For c = 7 To DerCol Step 2 'Loop column 7 (G) filled with the last jump of 2, it means that the following loop c will be worth 9, then 11, ...
        MySom = MySom + Cells(r, c) 'Sum the value of the variable line every 2 column by loop
        MyNb = MyNb + 1 'Count the number of column (there is no choice but ...)
    Next c 'Goes to the next c
    Sheets("File1").Cells(r, 5) = Round(MySom / MyNb, 2)
    MySom = 0
    MyNb = 0
Next r
 
For r = 3 To 22 'Loop on the lines whereas the number is fixed
    For c = 8 To DerCol Step 2 'Loop column 8 (H) to the last filled with jumps of 2, it means that the following loop c will be worth 9, then 11, ...
        MySom = MySom + Cells(r, c) 'Sum the value of the variable line every 2 column by loop
        MyNb = MyNb + 1 'Count the number of column (there is no choice but ...)
    Next c 'Goes to the next c
    Sheets("File1").Cells(r, 6) = Round(MySom / MyNb, 2)
    MySom = 0
    MyNb = 0
Next r
 
End Sub