Apply subtotal when I have a different range

Hello,
I tried to found a solution for my problem, but no succes through other threads.
I have a row with data, sometimes i have 1000 lines in row, other time I have 100 lines.
Because i don't want to lose data, I always apply automatic subtotal, I select range(A:B), and sum function. Selecting range A:A somethimes Excel crashes.
How can i determine the range? Let's say if I have 50 entries then the range is "Range(A1;B50)" this range must be inserted in subtotal function.

I hope I explained well my problem.
Thanks in advance.

Thanks, for reply.
My subtotal function looks like this:

Columns("A:B").Select
Selection.Subtotal GroupBy:=1, Function:=xlSum, TotalList:=Array(2), _
Replace:=True, PageBreaks:=False, SummaryBelowData:=True
ActiveSheet.Outline.ShowLevels RowLevels:=2
ActiveSheet.Outline.ShowLevels RowLevels:=2

I have 2 rows A and B, and applyed subtotal on them.
In VBA:
I can't manage how how to replace, Columns("A:B").Select, with my range for example A1:B183.