Data validation

[LaLa313]

Im trying to create a formula so that the data is a nonnegative number and it doesn't exceed 20% of the data in the column before it. The formula I have is =(C6<= (B6*0.2)) but it allows negative numbers. How do I make it not allow negative numbers? When I put =(0<=C6<=(B6*0.2)) it still doesn't work.

[Bob Phillips]

Try

=AND(C6>=0,C6<= (B6*0.2))