Fair enough - I think I'd searched before submitting this, but evidently not well enough :)

So what's the next step for this kata to come out of beta?

Good catch! JavaScript's floating point arithmetic tripped up my dynamic tests.

Fixed it, should work now.

Thanks, wthit56. I've randomised the tests, though I'm not sure if it's elegant!

I started writing an explanation - but this is better: http://floating-point-gui.de/

This is what you get when you analyse the problem properly before starting out. Kudos!