NonUnique index performance

What will be the difference between performance of NonUnique Index on Number & Varchar2? NonUnique index on Number will be faster or it is better in other consideration?

Any difference in performance between NonUnique index on number with negative values and without negative values?

SP

Any measurable difference would be extremely slight. The important think is to store numbers as numbers, dates as dates, characters as characters -- the issue then becomes irrelevant.