(1)5/9-1/3=5/9-3/9=2/9
(2)2/5+1/2=4/10+5/10=3/10
(3)1/3+5/9=3/9+5/9=8/9
(4)1/4+5/8=2/8+5/8=7/8
(5)1/3+5/6=2/6+5/6=7/6
(6)5/8-1/4=5/8-2/8=3/8
(7)3/4+1/8=6/8+1/8=7/8
(8)4/5-1/4=16/20-5/20=11/20
(9)2/3+1/6=4/6+1/6=5/6
(10)2/7+1/2=4/14+7/14=11/14
(11)7/8-3/4=7/8-6/8=1/8
(12)1/2-1/7=7/14-2/14=5/14
(13)5/12+1/6=5/12+2/12=7/12
(14)1/2+6/7=7/14+12/14=19/14
(15)3/5+1/6=18/30+5/30=23/30
望采纳...0.0