Multiple Data Validation?

[OverKnight]

From another post, I learned how to allow only one entry per a range:

Select the cells in the range (say A1:A3) and enter data validation:
Custom, Formula =IF(COUNTA($A$1:$A$3)<=1,1,0)

In addition to the above, is there a way to permit only the number one (1) to be entered?

Thank you.

 

[T. Valko]

From another post, I learned how to allow only one entry per a range:

Select the cells in the range (say A1:A3) and enter data validation:
Custom, Formula =IF(COUNTA($A$1:$A$3)<=1,1,0)

In addition to the above, is there a way to permit only the number one (1) to be entered?

Thank you.

Try this...

=AND(COUNTA(A$1:A$3)<2,COUNTIF(A$1:A$3,1)=1)

 

[OverKnight]

Works perfectly, Biff! Thanks very much!

 

[T. Valko]

Works perfectly, Biff! Thanks very much!

You're welcome. Thanks for the feedback!