I have two columns..I have written the below example to explain

A B
1 a
2 b
3 c
4 d
5 e
6 f

what I want to do is put a dropdown menu on a sheet, that when "1" is
selected, in another cell, "a" would be displayed, and so on for all
the way to "6"/"f" I have selected all of the numbers in the A column
and name/defined it as "points". I have done the same with all in
column B and names it "mm". I basically want someone to be able to
select one of the points, and have it automatically display the mm
value....any help would be greatly appreciated..

Scott