1 1/7*6.8+60/7*0.68

问题描述:

1 1/7*6.8+60/7*0.68

1/7*6.8+60/7*0.68
=1/7*6.8+6/7*6.8
=6.8*[1/7+6/7]
=6.8*1
=6.8