помогите плиз (15-9 1/3):2/3---------------------(19 2/3-11 7/9)*9/71=?

[(15 - 9 1/3) : 2/3] / [(19 2/3 - 11 7/9) * 9/71] = 8 1/2,1)  15 - 9 1/3 = 14 3/3 - 9 1/3 = 5 2/3.2) 5 2/3 : 2/3 = 17/3 * 3/2 = 17/2 = 8 1/2,3) 19 2/3 - 11 7/9 = 19 6/9 - 11 7/9 = 18 15/9 - 11 7/9 = 7 8/9,4) 7 8/9 * 9/71 = 71/9 * 9/71 = 1,5) 8 1/2 : 1 = 8 1/2