265/5*18-538
=53*18-538
=954-538
=416
3/8*[8/9/(5/6-3/4)]
=3/8*（8/9*12）
=3/8*32/4
=3
(8.8-23.4*1/3)/5/9
=（8.8-7.8）*9/5
=1*9/5
=1又4/5