3 Could not deduce `PrelBase.Num a'
4 (arising from an instance declaration at tcfail042.hs:18)
5 from the context: (PrelBase.Eq a, PrelBase.Show a)
6 Probable cause: missing `PrelBase.Num a'
7 in instance declaration context
8 When checking the superclasses of an instance declaration
11 Compilation had errors