Excel

I am deducting two tables and I am using V-Lookup. However, in one of the
tables I dont have all the headings as in table 1. When I subtract then I
get #N/A. To correct this, I am using ISERR but it returns False.

Formula I am using

=VLOOKUP($B81,$B$8:$L$32,COLUMNS($C$8:L$8),0)-VLOOKUP($B81,$B$37:$L$58,COLUMNS($C$37:L$37),0)

With Error formula

=ISERR(VLOOKUP($B81,$B$8:$L$32,COLUMNS($C$8:L$8),0 )-VLOOKUP($B81,$B$37:$L$58,COLUMNS($C$37:L$37),0))

What can I do to make sure that when there is a value in the first tables,
brings that value.

Regards,
jose