>>106026942
the google calculator at least shows you how it interprets the equation.
I was taught the donkey bridge "meneer van dale wacht op antwoord" which as you can see puts multiplication before division in which case the answer would be 6/(2*(1+3)).
Honestly if there's any room for doubt, not using parentheses is poor practice and should be discouraged. This is the same thing as those job interviews where they ask you to interpret weird looking unreadable C syntax. You're supposed to be able to figure it out but nobody actually writes code that way.