You should try to 1. destill which basic operations are necessary on the types Int, MyNum to make your algorithms work, 2. write a type class for these operations, 3. write type class instances for Int and MyNum, 4. write a generic algorithm that works for all members your class, which ideally looks almost identical to the specific code you already have. I dare say this is a common way of reducing boilerplate code in Haskell. BTW, you should consider Numeric.Natural instead of Int for Peano addition. Cheers Olaf