50: (11 8,23+5 15,23) - (6 1,5-2 3,5) : 9

помогите решить

1) 11 8/23 + 5 15/23 = 16 23/23 = 17

2) 6 1/5 - 2 3/5 = 5 6/5 - 2 3/5 = 3 3/5

3) 50 : 17 = 50/17=2 16/17

4) 3 3/5 : 9 = 18/5 * 1/9 = 2/5

5) 2 16/17 - 2/5 = 2 (16*5-17*2) / 17*5 = 2 46/85