On the face of it, 2 steps

Presuming the range is cols A to D, with the lowest number zero
just place in say, E1: =MIN(A:D)
to retrieve the lowest number

Then select cols A to D, click Edit Replace
to replace that lowest number with the desired value
(Click Replace All)

P/s: You should always post your *complete* query in the message area, not
embed half of it in the subject line, half in the message area. The subject
line is meant to contain just a brief, key summary descript of your query.
--
Max
Singapore
http://savefile.com/projects/236895
xdemechanik
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"jerry" wrote:
determine lowest number in several columns and replace lowest numb
with value from a specific cell