Problems 16-30
Review the definition of the associative and commutative properties. Remember that when the commutative
property is used, the order in which the elements appear from left to right is changed, but the grouping
is not changed. When the associative property is used, the elements are grouped differently, but the order
in which they appear is not changed.
Note: Homework Hints are given only for the levels 1 and 2 problems.