[math-fun] build table of multiplicative inverses without dying of embarrassment

HUH? The inverse of 42 mod 239: In[1131]:= Convergents[42/239] Out[1131]= {0, 1/5, 1/6, 3/17, 13/74, 42/239} In[1132]:= Mod[74*42, 239] Out[1132]= 1 --rwg