А) 1/27+5/9+1/3; б)2/9+5/6+1/18; в)2/15+1/5+3/10; г)3/8+5/12+1/24; д)1/4+3/8+5/16; е)5/7+3/14+1/21.

а) 1/27 + 5/9 + 1/3 = 1/27 + 15/27 + 9/27 = 25/27 б) 2/9 + 5/6 + 1/18 = 4/18 + 15/18 + 1/18 = 20/18 = 1 цел.2/18 = 1 цел.1/9 в) 2/15 + 1/5 + 3/10 = 4/30 + 6/30 + 9/30 = 19/30 г) 3/8 + 5/12 + 1/24 = 9/24 + 10/24 + 1/24 = 20/24 = 5/6 д) 1/4 + 3/8 + 5/16 = 4/16 + 6/16 + 5/16 = 15/16 е) 5/7 + 3/14 + 1/21 = 30/42 + 9/42 + 2/42 = 41/42