The result of the arithmetic expression "6+6+6+6x0" depends on the order of operations also known as BIDMAS/BODMAS (Brackets, Indices, Division/Multiplication, Addition/Subtraction). According to this rule, multiplication and division should be done before addition and subtraction.
So the expression "6+6+6+6x0" becomes:
6+6+6+(6*0)
6+6+6+0
which equals 18.