Дроби к наименьшему общему знаменателю 1/2,1/6и2/3; 1/4,5/7и9/28; 1/5,11/20и3/10; 3/4,7/8и3/16; 2/3,2/15и4/5; 1/2,1/9и5/6.

1/2+1/6+2/3 = (3+1+4)/6 = 8/6
1/4+5/7+9/28 = (7+20+9)/28 = 36/28
1/5+11/20+3/10 = (4+11+6)/20 = 21/20
3/4+7/8+3/16 = (12+14+3)/16 = 29/16
2/3+2/15+4/5 = (10+2+12)/15=24/15
1/2+1/9+5/6 = (9+2+15)/18 = 26/18