An expression 9 + 5 * 2 has two possible interpretation:
(9 + 5) * 2 and 9 + (5 * L)
The associativity of '+' and '*' do not resolve this ambiguity. For this
reason, we need to know the relative precedence of operators.
The convention is to give multiplication and division higher precedence than addition and subtraction.
Only when we have the operations of equal precedence, we apply the rules of associative.
So, in the example expression: 9 + 5 * 2.
We perform operation of higher precedence i.e., * before operations of lower precedence i.e., +. Therefore, the correct interpretation is 9 + (5 *).