1: 3 × (9 - 3 ÷ 3)2: 3 × (9 - (3 ÷ 3))3: (9 - 3 ÷ 3) × 34: (9 - (3 ÷ 3)) × 3一共有4种方法
[9－﹙3÷3﹚]×3
(9 - 3 ÷ 3) × 3
