5/9×86又7/11+5/11×9/1+4×5/11简算
解,得：
(5/9)*(86又7/11)+(5/11)*9+4*(5/11)
==(5/9)[86+(7/11)]+9*(5/11)+4*(5/11)
==(5/9)*86+(5/9)*(7/11)+9*(5/11)+4*(5/11)
==(5/9)*86+(5/9)*[(2/11)+(5/11)]+9*(5/11)+4*(5/11)
==(5/9)*86+(5/9)*(2/11)+(5/9)*(5/11)+9*(5/11)+4*(5/11)
==(5/9)*86+(5/9)*(2/11)+(5/11)[(5/9)+9+4]
==(5/9)*86+(5/9)*(2/11)+(5/11)[13又(5/9)]
==(5/9)*86+(5/9)*(2/11)+(5/11)*13+(5/11)(5/9)
==(5/9)[86+(2/11)+(5/11)]+(5/11)*13
==(5/9)[86又(7/11)]+(5/11)*13
==(5/9)[86又(7/11)]+[5又(10/11)]
==(5/9)[92又(6/11)]
==5090/99