Try this:

=IF(D30,LOG(C3/F3),""&TEXT(LOG(C3/10),"#.#"))

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HTH,

RD
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Please keep all correspondence within the Group, so all may benefit!
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"Kaputa" wrote in message
...
=IF(D30,LOG(C3/F3),""&LOG(C3/10)) gives me the two options that I want.
Thanks to all who responded. Now, the first part is rounded to 1 decimal
place, ie 0.0, because I chose so in custom mode. When the second part is
true, however, I loose the custom formatting and get several decimal
places
added. How do I prevent this?