I have an excel containing 13 worksheets. That's 1 worksheet for each month,
then a summary worksheet that each month's total average link-pastes into.
So in the summary worksheet, each 12 months average is shown in separate
cells and below is an entire year summary cell where these 12 totals are
averaged.
The problem is the entire year summary average cell an error #DIV/0!
I think it's because the months that we have not reached this year do not
have a total data yet. These months average cells also show the #DIV/0!

How can I fix the Average formula to work with the cells that have data and
skip the other months so an average for the months with values is shown?

Example:
In the summary worksheet:
"200" is in cell A-1, this is a link paste from another worksheet "May"
average for May.
"DIV/0!" is in cell A-2, this is a link paste from another worksheet "June"
average for June that does not contain any counts yet.
"DIV/0!" is in cell A-3, this cell contains formula "=AVERAGE(A1,A2)

Thank-you for any help!