[mrtg] math in Target

[R Dicaire]

Hi...I'm pulling data via snmp that returns a 5 char result:

UCD-SNMP-MIB::ucdExperimental.16.2.1.3.1 = Gauge32: 39000

This is CPU temperature. My target gets CPU and motherboard temps,
both return 5 char as results.
I'm trying to perform math on these results but it looks like I don't
understand the docs on how this is performed.
My target line:

Target[daw1_temps]: .1.3.6.1.4.1.2021.13.16.2.1.2.1:public at daw1 / 1000
&.1.3.6.1.4.1.2021.13.16.2.1.2.2:public at daw1 / 1000

(Forgive any linewrapping, I have left the requisite white space
around the math expr)

Is this not possible on the target line, or must some other means be
used to get the desired result, and if so, how?
Thanks

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