д) 2/9 + 1/12 = 8/36 + 3/36 = 11/36 = 11/36
е) 7/24 + 1/60 = 35/120 + 2/120 = 37/120 = 37/120
ж) 1/42 + 2/63 = 3/126 + 4/126 = 7/126 = 1/18
з) 5/12 + 3/20 = 25/60 + 9/60 = 34/60 = 17/30