The math is simply the difference between the values in two cells, but one of
the cells will change each time the table is updated.

For example, Row 1 headers are Apr, Mar, Feb, Jan, etc. and the last column
is Prior Year. In At any given time, I want the value for the most recent
month minus the prior year. How do I get it to automatically pick up the
last non-blank cell in the row?

Thanks