18/5+10/7+18/13+10/1 은?
5/18+7/10+13/18+1/10
=5/18+13/18+7/10+1/10
=18/18+8/10
=1+4/5
=9/5
5/18+7/10+13/18+1/10
=5/18+13/18+7/10+1/10
=18/18+8/10
=1+4/5
=9/5