помогите решить пример (4 6/7 : (5/6+8/21)-2 5/13)*8 2/3

(4 6/7 : (5/6+8/21)-2 5/13)*8 2/3=30 22/49

5/6+8/21=35/42+16/42=51/42

4 6/7:51/42=34/7*51/42=867/147=289/49

289/49-2 5/13=3757/637-1519/637 =2238/637

2238/637*8 2/3=2238/637*26/3=1492/49=30 22/49