1 и 2, 1 и 3, 1 и 4, 1 и 5, 1 и 6, 1 и 7, 1 и 8, 1 и 9 1 и 10.
2 и 3 , 2 и 4, 2 и 5, 2 и 6, 2 и 7, 2 и 8 , 2 и 9 , 2 и 10.
3 и 4 , 3 и 5, 3 и 6, 3 и 7, 3 и 8, 3 и 9, 3 и 10.
4 и 5 , 4 и 6, 4 и 7, 4 и 8, 4 и 9, 4 и 10.
5 и 6, 5 и 7, 5 и 8, 5 и 9, 5 и 10.
6 и 7, 6 и 8, 6 и 9, 6 и 10.
7 и 8, 7 и 9, 7 и 10.
8 и 9, 8 и 10.
9 и 10.
Ответ: 45 способами