1) 9/10 и 4/5 = 8/10
9/10 > 8/10
2) 4/7 и 2/3
4/7 = 12/21
2/3 = 14/21
12/21 < 14/21
Ответ: 1) 9/10 > 4/5; 2) 4/7 < 2/3