(8/9-1/4+5/6)÷1/36
= 8/9*36-1/4*36+5/6*36
=32-9+30
=53
3/8÷（3/4-1/8）
= 3/8÷5/8
= 3/8*8/5
=3/5
（2-0.6）÷7/15
=1.4*15/7
=3
23×17/24
=(24-1) ×17/24
=24×17/24-17/24
= 17 -17/24
=17又7/24
2/7+5/7×7/15
=2/7+1/3
=6/21+7/21
=13/21