Random number generator?

I’d like to practise numbers in my ‘foreign’ languages. Once upon a time I wrote myself a very simple programme to generate random numbers in (Super)BASIC on my Sinclair QL. It worked well, but these days I’ve forgotten how to do things like that. Is there a free RNG available? If not, what is a good way to practise?

Stupid me! I’ve just googled it and there seems to be a lot of choice…