I would setup conditional format by using Rank function, but the REF value
still needs another calcualtion before it can be put into the function. I
tried to write like this,

=rank(a1/b1,(a$1:$3/b$1:b$3)) or =rank(a1/b1,(a$1/b$1,a$2/b$2,a$3/b$3))

They were not acceptable with an alert window saying regular mistakes.
My question is, is the cell reference the only thing in the REF than any
other values?? Can I just write values for the REF like I did, or I have to
occupy more cells to keep median values?? Thanks!!