Deductions & credits

Thanks for trying to simplify @pk.  @GeorgeM777 @JohnB5677 

Here are the specifics in one timeline for clarity:

Original shares:

2002 bought 100 shares of AT&T

11/18/2002 - reverse split to 20 shares

3/13/2003 - Sold the full 20 shares of AT&T

 

11/22/2002 - Received 12 spinoff shares of Comcast Corp

2/2007 reverse split to 6 shares

5/2007 split to 18 shares

2/2017 split to 36 shares

2022 sold 36 shares

Trying to determine the cost basis for the 36 shares of Comcast sold