Quoted text is from the authors' descriptions of the programs.
I've added some extra background information which I hope will be informative. However, note that I was not one of the judges so this information is not definitive. The mathematical programs do some sort of calculation, with the result bit-pattern to be interpreted as one or more numbers. Graphical programs make use of the store as a bitmapped display, and the result bit-pattern was typically interpreted as an animation, or as a symbolic representation of something. The UK schools winner Brendan Campbell wrote a program to do integer division, giving quotient and remainder.