The formula to sum "C" in these four tables escapes me, if it is even possible.
My SUMIF, SUMIFS & SUMPRODUCT search comes up with no "four-way" solution.

Assume Columns A - B & D - E.

Where the sum of "C" would = 18.

Howard


Table 1 Table 2
A 4 X 7
B 3 Y 6
C 8 Z 3


Table 3 Table 4
B 1 C 8
C 2 X 7
D 5 Y 9