Well, lets look at your original statement...
"I have 160 numbers in 160 numbers in column B..."

There is no need to repeat those numbers within the LOOKUP statement - all
you need to do is reference the ranges involved. Since you are using A1 as a
lookup value, I will assume that your lists start on row 2. If that's the
case, then a formula like
=LOOKUP(A1,A$2:A$161,B$2:B$161)
will give you the results you want/expect - as long as the values in column
A are in ascending order.

If there is a possibility of the data in column A being out of order, you're
better off with a VLOOKUP()
=VLOOKUP(A1,A$2:B$161,2,False)
which will achieve the same thing without the items in column a needing to
be in an ordered sequence.

"Lookup formula limitation?" wrote:

Thanks,
But, how do you fix the limitation?

"JLatham" wrote:

I have a sneaking suspicion that it's not representative of the real
situation, but may be one that he used to try to determine where it was
failing at.
The root cause of the problem may even be something we've not mentioned yet,
such as stack or buffer size limits for the arrays involved when LOOKUP() is
used in this fashion - which would make his determined limit of 80 elements
not a constant, but a variable based on the type of elements in the arrays.

"Pete_UK" wrote:

In your example it looks like you want to multiply by 10 - can't you
just do:

=A1*10

or is your example not representative?

Pete

On Aug 17, 3:17 am, Lookup formula limitation? <Lookup formula
wrote:
I have 160 number in column A and 160 numbers in Column B.....

Lookup let me to compair only 80?
=lookpu(A1,{1,2,3,4,5.........160},{10,20,30,..... .......1600})

How come excel let me do up to 80, not 160?