Hi mark,

Put 1 through 8 in A1:H1.

In A4 enter =LOOKUP(9.99999999999999E+307,A1:H1)

This returns 8.

In A5 enter =LOOKUP(9,A1:H1)

This also returns 8.

As long as the Look_Up value is larger than any value in the Look_Up Vector,
it will return the last number in the vector.

Now change D1 to 500. A4 returns 8 and A5 returns 3. The A4 lookup value
is larger than 500 so it returns 8. The A5 lookup value is less than 500 so
it returns the 3.

Beam up help on the worksheet and check out LOOKUP and parse the examples
and the lookup rules.

The huge lookup value in the A4 formula is, I believe, the largest number
Excel will deal with, so it would, of course, return the last value in the
vector no matter how large it was. But the lookup value really only needs
to be larger than any value anticipated within the lookup vector to return
the last value in the vector.

HTH
Regards,
Howard

"Mark" wrote in message
...
Hello

I understand what the above function does, however I would like to know
how
it works, in obtaining the first available cell with data in the range
from
right to left....Thanks Mark