John,

Assuming there is a space between the value and the suffix, you could strip
the numeric value out of a cell this:

=LEFT(M30,FIND(" ",M30))

This will return all the characters in the string in M30 up to the space -
this should be your numbers. You could then use this idea to subtract the
numeric elements of two cells from each other thus:

=LEFT(M30,FIND(" ",M30))-LEFT(M31,FIND(" ",M31))

Hope this helps - unledd there isn't a space between the number and the
suffix, in which case I'll have to think again!

Cheers

Pete







"John Sayaff" wrote:

I have measurement data from an ATE system where the results are given as
both a number and 'unit' letters for example 22.3 dB, 2.109 MHz, 12.06 V and
0.175 A. To calculate temperature drift from these readings, I need to
subtract cells that contain both a number and a letter i.e.

2.012 MHz - 2.005 MHz = 0.007
does not matter if the answer contains the 'units' or not.

anyone know how I can achieve this ?