Question

7.8除{2又三分之二乘（1又八分之五加?）减1.1}减十五分之二除三分之二＝1又五分之四

Answer 1

7.8÷[2又2/3×(1又5/8+?)-1.1]-2/15÷2/3=1又4/5

7.8÷[2又2/3×(1又5/8+?)-1.1]=1又4/5+1/5

2又2/3×(1又5/8+?)-1.1=7.8÷2

2又2/3×(1又5/8+?)=3.9+1.1

1又5/8+?=5÷2又2/3

=1又7/8-1又5/8

=1/4