简算,1/5÷9+1/15÷9/8

问题描述:

简算,1/5÷9+1/15÷9/8
一定是简算

=1/5×1/9+1/15×8/9
=1/5×1/9+1/15×8×1/9
=(1/5+8/15)×1/9
=11/15×1/9
=11/135