we know that
The associative property of addition says that changing the grouping of the addends does not change the sum
in this problem
we have
(16+22+18)=56
First way
(16+22)+18
Remember that parentheses tell us to do something first
=(38)+18
=56
Second way
16+(22+18)
Remember that parentheses tell us to do something first
=16+(40)
=56
Notice that both ways sum 56