Im in 2nd year of math now...so I know algebra but I was reading this from this website: "Substitution Every time we replace a part of an expression with a value or another expression, we are using the technique of Substitution. And, every time a substitution is performed, parentheses are used!" http://www.math.ohio-state.edu/~mcginnis/08Au%20M132N/Algebra%20Fundamentals.pdf [Broken] My question is... when you substitute into an expression...eg. e^x Sub in 2x+1 ... Maybe a bad eg since im typing it ...but if you were writing it on paper... I wouldnt even think about it...id just write e^(2x+1) ...(No Brackets) Or sub 2x for x in x+1 ...Id just write 2x+1 or sqrt(x^2+y^2) ...evaulated at x=1=y Id just go sqrt(1^2+1^2) But do you ALWAYS imagine brackets in your head first...when youre doing these... Because im really worried that everyone else is doing this except me ..