Here's the formula I posted:
=SUMPRODUCT((MOD(COLUMN(H8:AH8),3)=2)*ISNUMBER(MATCH(H8:AH8,{1,2,3,4,5},0)))
Your interest is in its first functions
1)COLUMN()
That function returns the column number of the reference.
Col_A is 1, Col_B is 2, etc
2)MOD()
The MOD function essentially peforms grade school division and returns the
"remainder". For example, if you divide 13 by 5, the grade school answer
would be 2 with 3 left over. The MOD function version would be =MOD(13,5),
which returns 3.
By combining the MOD and COLUMN functions, we can isolate every third
column, every 5th column, etc. In your specific case, you wanted every 3rd
column, beginning with Col_H. Col_H is col number 8....MOD(8,3)=2...so, by
applying that boolean (true/false) equation to every column in H through AH
the column numbers with a remainder of 2 would return TRUE (the others would
return FALSE). TRUE and FALSE, when used in a mathematical context, convert
to 1 and 0, respectively.
If you wanted to test values from every column, you'd just skip those first
functions:
=SUMPRODUCT(ISNUMBER(MATCH(H8:AH8,{1,2,3,4,5},0)))
Does that help?
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Regards,
Ron
XL2002, WinXP-Pro