Excel VBA: UDF Not Working; Please Explain?

[IGPOD]

I'm trying to learn how to perform User Defined Functions in Excel, and I thought this code (below) would be a winner on first pass; but it was not.

Public Function change2F() As Variant
Dim result As Variant
Dim sht As Worksheet
    change2F = (sht.Range("a:a") - 32) * 5 / 9
    change2F = result
        
End Function

Basically, I have in column A, a set of numbers from 0 to 100 (by 5's; representing Fahrenheit values) and I'm trying to get the Celsius equivalent to those numbers.


I have tried to toy with the code and keep getting "#VALUE!" errors

Can someone explain why this code isn't working? I've tried several different data types and combinations to no avail: Integer, Variance, Long ... nothing seems to be working.

What's going wrong with this code?