The question I have been given is essencially this:

Give a brief description, with some explanation, of which rational numbers between 0 and 1 have finite decimal expansions? [An example is 3/40 = 0.075, however 2/3 = 0.66666666666............]

I am truly

Please help.

I have looked on

http://mathworld.wolfram.com/DecimalExpansion.html
but I need more??? anyone???