I'm working on a student assignment were I need to annualize accounts
recievable.  I've been told, "Multiplying month-end accounts receivable
by 12 does not result in an annual accounts receivable figure."....OK,
so how do I get it from the average value if I don't multiple by 12?

Annualizing A/R doesn't seem to make sense.  It would be a meaningless
number.  Do you mean 'average' -- if so, add the twelve month end
balances and 'divide' by 12.  This would be much more meaningful - its
the measurement of how much is owed to you at any given time, on the
average.

maybe you should deduct the allowance for doubtful accounts and then
multiply by 12... i dunno, just a thought.

you know i think your teacher is talking about A/r turnover which
measures how often they turn their a/r into cash in a year...The value
is computed by dividing sales for the period by average accounts
receivable for the period, multiplied by the applicable factor to
annualize sales.  In your case, it would be multiplied by 12.