Hello Sumeet,
I assume, you have replicated your ECC table using SLT.
You can add a calculated column to your table via an ALTER TABLE statement (e.g. ALTER TABLE "<your table>" ADD ("<calculated_column_name> decimal(6,0) GENERATED ALWAYS AS ("<your_original_column>");).
This supplies the new calculated column for every insert or update (in case you have already data in your table, just do a simple update of each row). Of course only if you have values in your original column which can be converted.
But consider, that a calculated column is materialized and you have a little overhead for each insert/update.
Did you think about the creation of a simple calculation view using a projection with a calculated column to convert the value to a decimal value? This would avoid that you need additional storage for the decimal value on the db.
Best regards,
Florian