(2/3+1/8)×(1/2-9/19)
=2/3×1/2-2/3×9/19+1/8×1/2-1/8×9/19
=1/3-2/57+1/16-1/152
=1/48
(2/3+1/8)×(1/2-9/19)
=(16+3)/24×(19-18)/38
=19/24×1/38
=1/48
第二种比较简便
希望回答对你有用