The numeric value of the quantity associated with a leaf node n is denoted as Q(n).
each node n also has a value associated with it, represented as VAL(n), which can be computed in a recursive way as follows: if n is a leaf VAL(lc(n)) (n) VAL(rc(n)) otherwise (1) For any expression tree T for expression e with root node n root , the value of VAL(n root ) is exactly equal to the numeric value of the expression e. this gives a natural representation of numeric expressions, providing a natural parenthesization of the numeric expression.