Exercises 41 Exercises Exercise 1 Start with the grammar G6, repeated here: erootexp> : : = ( ) Modify it in the following ways: a. Add subtraction and division operators(-and/) with the customary prece- dence and associativity b. Then add a left-associative operator % between + and * in precedence. c. Then add a right-associative operators at lower precedence than any of the other operators