=
+
  |
 
= 
::=
+
|
::=
*
|
::= (
) | a | b | ca.) add subtraction and division operators (- and /) with the customary precedence and associativity.b.) then add a left associative operator % between + and * is precedence. c.) Then add a right associative operator = at lower precedence than any of the other operators.