random number without repeating?

[nonoi via OfficeKB.com]

i want to do the random number for every each cell without repeat the same
number?do you know how to solve my problem?

 

[Ragdyer]

Say you wanted 1 to 20 to be your numbers.

In an out of the way column, say Z, enter into Z1:
=RAND()
And copy down to Z20.

You can now enter this formula anywhere you wish, and copy down for 20 rows:

=INDEX(ROW($A$1:$A$20),RANK(Z1,$Z$1:$Z$20))

If you don't want consecutive numbers, you can make your own list of
numbers, or letters or even words.
Just enter them in say ColumnY, from 1 to 20, and try this:

=INDEX($Y$1:$Y$20),RANK(Z1,$Z$1:$Z$20))

 

[JE McGimpsey]

For most purposes, RAND() provides a pretty good approximation of unique
random numbers for relatively small sets.

If you mean random integers, see

http://www.mcgimpsey.com/excel/randint.html