(24,3:9/13-4,5*3 1/3):(56,81:2,3-18)

1) 24,3 : 9/13 = 24 3/10 : 9/13 = 243/10 : 9/13 = 243/10 * 13/9 = 27/10 * 13/1= 351/10 = 35 1/10;2) 4,5 * 3 1/3 = 4 5/10 * 3 1/3 = 4 1/2 * 3 1/3 = 9/2 * 10/3 = 3/1 * 5/1 = 15/1 = 15;3) 35 1/10 - 15 = 20 1/10 = 20,1;4) 56,81 : 2,3 = 24,7;5) 24,7 - 18 = 6,7;6) 20,1 : 6,7 = 3.Ответ: 3.