1) 2/11 < 3/11; 2/3 > 3/8, т.к. 16/24 > 9/24; 5/12 > 7/24, т.к. 10/24 > 7/24
2) 5/8 + 7/12 = 15/24 + 14/24 = 29/24 = 1 5/24
4 - 2 4/14 = 3 14/14 - 2 4/14 = 1 10/14 = 1 5/7
4 7/11 - 3 2/3 = (4 - 3) + (7/11 - 2/3) = 1 + (21/33 - 22/33) = 1 - 1/33 = 32/33
8 2/5 + 4 9/10 = 8 4/10 + 4 9/10 = 12 13/10 = 13 3/10 = 13,3
3) 2 2/3 + х = 3 5/6; х = 3 5/6 - 2 2/3; х = 3 5/6 - 2 4/6; х = 1 1/6
4) 13 1/4 - 3 5/6 = 13 6/24 - 3 20/24 = 12 30/24 - 3 20/24 = 9 10/24 = 9 5/12 (км) - прошли туристы во второй день; 13 1/4 + 9 5/12 = 13 3/12 + 9 5/12 = 22 8/12 = 22 2/3 (км) - прошли туристы за два дня
5) 8/17 = 24/51 > 7/17 = 21/51 (доп.множ.3)
8/17 > 23/51 > 22/51 > 7/17
Ответ: дроби 23/51 и 22/51 меньше 8/17 и больше 7/17