4/7 + 1/2 = 8/14 + 7/14 = 15/14 = 1 1/14
5/12 + 3/4 = 5/12 + 9/12 = 14/12 = 1 2/12 = 1 1/6
1/2 + 2/3 + 5/6 = 3/6 + 4/6 + 5/6 = 12/6 = 2
3/8 + 3/10 = 15/40 + 12/40 = 27/40
3/50 + 2/40 = 12/200 + 10/200 = 22/200 = 11/100 = 0,11
1/30 + 2/45 = 3/90 + 4/90 = 7/90