=FREQUENCY(A1:A13,A1:A13)

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HTH

Bob Phillips

(replace somewhere in email address with gmail if mailing direct)

"fiur" wrote in message
...
I got a worksheet with only 2 different numbers in each cell like this:
1
1
1
0
0
1
0
0
1
1
1

My question are how do I count the largest number of equal cells...