Standard practice didn't dictate where to put those brackets. It just said to use them so a problem isn't ambiguous. You chose to start your bracket where the division symbol was. Others may have put it before and then after the first 2. Don't you see? The standard did not say where to put the brackets, just to use them so your equation is clear. Again, modern standards do not state what you are claiming. Brackets could (not would) yield 1. Brackets could (not would) also yield 16 depending on where they were placed. The standards do not make any claim as to where to put those brackets because it is ambiguous meaning we don't know for sure where they would go.