Найдите значения выражения 20-18,6: (6 11/15 - 4 3/20)

20 - 18,6 : (6 11/15 - 4 3/20) = 12 4/5

1) 6 11/15 - 4 3/20 = 6 44/60 - 4 9/60 = 2 35/60 = 2 7/12
2) 18,6 : 2 7/12 = 18 6/10 : 2 7/12 = 18 3/5 : 2 7/12 = 93/5 : 31/12 = 93/5 * 12/31 = 36/5 = 7 1/5
3_ 20 - 7 1/5 = 12 4/5