如题所述
解
5/14+2/3
=15/42+28/42
=43/42
5/14+8/21
=30/84+32/84
=62/84
=31/42
5/14+6/14
=11/14
5/14+1/7
=5/14+2/14
=7/14
=12
祝你学习进步