exp -> exp addop term
exp -> term
addop -> +
addop -> -
term -> term mulop factor
term -> factor
mulop -> *
factor -> ( exp )
factor -> number

The First Set:
First(exp) = { (, number }
First(addop) = { +, - }
First(term) = { (, number }
First(mulop) = { * }
First(factor) = { (, number }