1/3-1/4=4/12-3/12=1/12,1/5+1/6=6/30+5/30=8/30=4/15,4/15+2/5=4/15+6/15=10/15=2/3,3/4+7/8=6/8+7/8=13/8,5/16-1/8=5/16-2/16=3/16,3/5-1/2=6/10-5/10=1/10,5/6+1/4=10/12+3/12=13/12,5/6-1/9=15/18-2/18=13/18
1/12 11/30 2/3 13/8 13/12 3/16 13/18 1/10