One way:

Z2: =VLOOKUP(Y2,A:B,2,FALSE)

In article ,
Ken wrote:

In Worksheet 1 Column A has a list of 1000 different names. For example,
cell A750 = "Ralph". Column B has a corresponding number to the values in
column A. For example, cell B750 = "55". Column Y has a list of names which
change dynamically. Column Z wants to return the corresponding numerical
value found in Column B. For example, if cell Y2 = "Ralph" I want cell Z2 to
have the value "55". What short formula (without 1000 nested statements) can
I write to do this in column Z?