Assume your Columns are A and B, and your rows go down to 20, Array enter
this formula (CTRL+SHIFT+ENTER):

=SUM(IF(A1:A20=B1:B20,1,0))

Change the column and row references to fit your data.

--
Regards,
Dave


"Lingyan Hu" wrote:

Imagine there are two columns of cells, each row of two cells are
corresponding to each other. How to find out the number of rows where the two
corresponding cells have the same value?