How to translate logical notation to Haskell syntax

Question

I\'ve recently picked up Haskell at uni and I\'m working my way through a set of exercises, here\'s a snippet of one that I can\'t make sense of:

\"Consider the followin

Answer 1

If it is just a exercise about modeling data (without code) the answer consist of adding constructor names to your grammar (and changing literal number to names). Something like

data Num = Zero | One | Two | Three | Four | Five 
         | Six | Seven | Eight | Nine
data Int = Single Num | Multiple Num Int
data Exp = ExpInt Int | ExpMinus Exp Exp | ExpMul Exp Exp
         | ExpMul Exp Exp

From that, you can write all sort of code, to parse and evaluate expressions.