B: A+B*(C-D)+E/(C-D)N 三元式:(1)(CD (2)(*B(1)) (3)(+A(2) (5)(^(4)N) (6)(/E(5)) (7)(+(3)(6))三元式: (1) ( - C D ) (2) ( * B (1) ) (3) ( + A (2) ) (4) ( - C D ) (5) ( ^ (4) N ) (6) ( / E (5) ) (7) ( + (3) (6) ) 例 : A + B * ( C - D ) + E / ( C - D ) ^N