Depending on where in the world you learned math, as Mashable reported, determines how you can solve the problem.
There is the PEMDAS method: the order of operations is Parentheses, Exponents, Multiplication, Division, Addition, Subtraction, typically from left to right.
There is also the BODMAS method: Brackets, Orders, Division, Multiplication, Addition, Subtraction.
So, the answer is 1.
The answer also is 16.