You ve to test the asc/desc functionality

So.. 

Enter few random numbers,  & test for asc & desc

Enter all same numbers like 1,1,1,1 etc & see the behaviour
of the prog 

if prog accepts only numbers then try : spl characters
alphabets etc 

ther might be many possibilities .. try to see how it
behaves if invalid data is entered

1.Enter few numbers in random order.
2.Check whether it is displaying in Ascending or Descending 
order.
3.If same number is entered several times then the number 
can be distinguished by ROW ID(Data base concept).
4.Enter decimals in between two numbers (Like 25,26.08,27)& 
see whether it is displaying in Ascending or Descending 
order.
5.And but obvious check for alphabets,spaces,special 
characters,it should not accept it.

1) enter both +ve and -ve numbers and sort.
2) Enter decimal numbers as .01,.001,.0001
3) Enter numbers in asc/desc order and try to sort.
4) enter numbers with 0 preceding them like 010,08,09,011.
5) try entering large numbers,99,999,9999,99999
6) enter same numbers.

Hope this helps.correct me if I am wrong.