1) 2 и 1, 4 и 2, 6 и 3, 8 и 4, 10 и 5, 12 и 6, 14 и 7. 2) 1 и 3, 2 и 6, 3 и 9, 4 и 12, 5 и 15. 3) 7 и 1, 8 и 2, 9 и 3, 10 и 4, 11 и 5, 12 и 6, 13 и 7, 14 и 8. 15 и 9. 4) 1 и 5, 2 и 6, 3 и 7, 4 и 8. 5 и 9, 6 и 10, 7 и 11, 8 и 12, 9 и 13, 10 и 14. 11 и 15.