[Haskell-cafe] money type ?

Good day all, my budding ledger program could not balance transactions exactly because of rounding error with Double. I *think* I got it working better with Rational (it was late). Another suggestion from #haskell was to multiply all money by 100. I'm tracking multiple currencies/commodities with varying precision so this gets a bit more complicated. Is there a type or library out there that's good for representing money and other quantities while avoiding rounding errors ? Best - Simon