Вычислите: а) 1/5 + 3/5 б) 1/2 + 1/2 в) 7/10 + 4/10 г) 3/8 + 5/8 д) 5/16 + 3/16 е) 3/20 + 7/20 ж) 8/19 + 1/19 з) 7/91

а) 1/5 + 3/5 = (1 + 3)/5 = 4/5;

б) 1/2 + 1/2 = (1 + 1)/2 = 2/2 = 1;

в) 7/10 + 4/10 = (7 + 4)/10 = 11/10;

г) 3/8 + 5/8 = (3 + 5)/8 = 8/8 = 1;

д) 5/16 + 3/16 = (5 + 3)/16 = 8/16 = 1/2;

е) 3/20 + 7/20 = (3 + 7)/20 = 10/20 = 1/2;

ж) 8/19 + 1/19 = (8 + 1)/19 = 9/19;

з) 7/91 + 13/91 = (7 + 13)/91 = 20/91.