VLookup Troubleshooting #N/A

[IrishEyes]

I am working on a sheet that will pull the detail text associated with a
number, after the number is typed.

I currently am using:
=IF(A4<>"",VLOOKUP(A4,openwork,2,FALSE),"")
My array is approximately 8 columns by up-to 1000 rows.

I have double and triple checked that the number I am looking up is in fact
within the array, and I have made sure that both sheets have numbers
formatted as numbers (not text).

Any ideas on what to look for next?

 

[Dave Peterson]

Checking (and changing!) the format is not enough.

Debra Dalgleish has lots of notes on troubleshooting =vlookup():
http://contextures.com/xlFunctions02.html#Trouble