In the previous section, a mathematical variable was also described as an unassigned variable.
Unassigned variables have their own name as their value.
This is the default condition for a variable until you assign it a value. It delays evaluation of an expression. You have seen an example of this already. Every time Maple evaluates a statement, it checks to see if it knows any other expressions that could be re-evaluated in light of the new information. An exception to automatic full evaluation is in procedures, which is discussed later.