JDA wrote...
I'm trying to do a Vlookup type function where I would return a speed
value
from one table to another, but I can't figure out how to make it work.
the
source data table looks like this:

[reformatted using underscores instead of tabs]
SubDv_____From___To____MPH
Squamish___0______3.5__15
Squamish___3.5___10.9__20
Squamish__10.9___42____25
....

If the value in the From column is always just the value from the To
column in the row above, and the From column is in ascending order, you
don't need to consider the To column, and you have a simple lookup
against the From column. Use VLOOKUP. If the entire table above were in
A1:D4, and the MP value you wanted to lookup were in cell X99, the
formula would be

=VLOOKUP(X99,$B$2:$D$4,3)