6/5+4/3-3/1
=18/15+20/15-45/15
=-7/15
5/4+10/7-20/13
=455/364+520/364-560/364
=415/364
8/7-12/5+6/1
=40/35-84/35+11760/35
=11716/35
6/5+4/3-3/1
=18/15+20/15-45/15
=-7/15
5/4+10/7-20/13
=455/364+520/364-560/364
=415/364
8/7-12/5+6/1
=40/35-84/35+11760/35
=11716/35