(19又4/9+9又4/19)÷(2又7/9+1又6/19)
=(175/9+175/19)÷(25/9+25/19)
=[175×(1/9+1/19)]÷[25×(1/9+1/19)]
=175÷25
=7
(19 4/9+9 4/19)÷(2 7/9+1 6/19)
=(175/9+175/19)÷(25/9+25/19)
=(175x28/171)÷(475/171+225/171)
=(4900/171)÷700/171
=4900/171x 171/ 700
=7
7 100%对
能写清楚点吗?是194/9还是19*4/9??????