I have columns of data grouped by date, and the number of names on a given
day are variable. I want to lookup the number associated with a given Name
from the previous day, and if the name did not exist on the previous day I
want to use a simple formula from data on that same line.

I think its a VLOOKUP but the lookup range would need to be variable where
the lookup range for any day is the range of rows from the previous day. In
this example, for 1/2/08, the Number for John (47) needs to be pulled from
John on 1/1. I assume it would be an if statement where if the Name occurs
on the previous day it does a VLOOKUP for the Number, and when it is a new
Name I use a formula (i.e. D3/D4)

Date Name Number
1/1/07 John 47
1/1/08 Mary 22
1/2/08 John 47
1/2/08 Bill 12
1/2/08 Sue 44

Thank You,
Bill Owens