Because, I learned the laws of math, and it clearly states this
1. Brackets go first
2. Division / Multiplication are equal
3. Addition / Subtraction are equal
4. All equations must be done LEFT to RIGHT
The answer can be 1 or 16 depending on what mathematical law you use under the laws of BOMDAS as you outlined the answer is 16 under the laws of PEMDAS the answer is 1.