7/8*[6/7-(1/21+3/7)]
问题描述:
7/8*[6/7-(1/21+3/7)]
答
7/8*[6/7-(1/21+3/7)]
=7/8*[6/7-10/21]
=7/8*[18/21-10/21]
=7/8*8/21
=1/3