(9-9)/9+9+9=18
9*(9/9+9/9)=18
(9÷9+9÷9)×9=18 （1+1）×9=18 2×9=18
9*(9/9+9/9)=18(9/9+9/9)*9=18√9+√9+9+9-9=18
(9-9)*9+9+9
