А)13/20 и 9/16; 13/20*4/4 и 9/16*5/5; 52/80 > 45/80; 13/20>9/16; б)7/10 и 6/25; 7/10*5/5 и 6/25*2/2; 35/50 > 12/50; 7/10>6/25; в)8/15 и 12/25; 8/15*5/5 и 12/25*3/3; 40/75 > 36/75; 8/15>12/25; г)5/6 и 7/8; 5/6*4/4 и 7/8*3/3; 20/24 < 21/24; 5/6 < 7/8; д)3/16 и 2/2; 3/16 < 16/16; 3/16<2/2; е)9/33 и 5/77; 3/11 и 5/77; 21/77 > 5/77; 9/33>5/77; ж)7/60 и 11/20; 7/60 < 33/60; 7/60 < 11/20; з) 4/5 и 2/7; 4/5*7/7 и 2/7*5/5; 28/35 > 10/35; 4/5 > 2/7.