I have a column of data which is calculated based on the column adjacent to
it. I want to create an IF statement that will check to see if the number in
the column is div/0 or #num! and if it is, display the value above it instead
of trying to calculate something.

ex
a b c d

1 1 4
2 4 7
3 6 9
4 #num! 9***

this forumla doesn't seem to work =if(a4=#num!,b3,a4+3)

how do i say the logical statement a4=#num! or div/0?