1) 1/2 + 1/3 2) 1/4-1/5 3)1/6×1/12 4) 2/3-4/27 5) 7/9+5/12 6) 11/12-5/18 7) 17/20+11/15

1) 1/2 + 1/3 = (3+2)/6 = 5/6
2) 1/4 - 1/5 = (5-4)/20 = 1/20
3) 1/6 * 1/12 = 1/72
4) 2/3 - 4/27 = (18-4)/27 = 14/27
5) 7/9 + 5/12 = (28+15)/36 = 43/36 = 1 7/36
6) 11/12 - 5/18 = (33-10)/36 = 23/36
7) 17/20 + 11/15 = (51+44)/60 = 95/60 = 1 35/60 = 1 7/12

1)1/2+1/3=3/6+2/6=5/6
2)1/4-1/5=5/20-4/20=1/20
3) 1/6×1/12=1/72
4) 2/3-4/27=18/27-4/27=14/27
5) 7/9+5/12=28/36+15/36=43/36= 1 7/36
6)11/12-15/18=66/72-60/72=6/72=1/16
7)17/20+11/15=51/60+44/60=95/60=1 35/60