is this what you require?
if this gives you the desired results
SELECT
ID
, value1
, value2
, value3
, value1 / value2 * value3 AS finalvaluetest
FROM yourtable
then
UPDATE yourtable
SET finalvalue = value1 / value2 * value3
________________________________________________________________
you can lead a user to data....but you cannot make them think
and remember....every day is a school day