Hi!

One way:

I assume your list of numbers is in Col A1:A1000 and col B is empty.

In B1 put =IF(COUNTIF($A$1:$A$1000,A1)=1,"",COUNTIF($A$1:$A$ 1000,A1))

Copy this down to B1000.

This will show alongside the multiple entries the number of times they
occur.

Alf