А) -3,6 - 4,7 = -8,3
б) 6,3 - ( -8,1) = 6,3 + 8,1 = 14,4
в) 4 и 1/3 - 5 и 2/7 = 4 и 7/21 - 5 и 6/21 = -20/21
г) -6 и 5/24 - (-5 и 13/30) = -6 и 5/24 + 5 и 13/30 = -6 и 25/120 + 5 и 52/120 = -(6 и 25/120 - 5 и 52/120) = -(5 и 145/120 - 5 и 52/120) = -93/120 = -31/40