( 1 2/9 + 1 1/6) * ( 2 - 1

(1 2/9 + 1 1/6) (2 - 1 25/42) = 2 целых 7/18 17/42 = 731/756
1) 1 целая 2/9 + 1 целая 1/6= 2 целых + 4/18 + 3/18=2 целых 7/18 
2) (2 - 1 целая 25/42) = 1 целая 42/42 - 1 целая 25/42 = 17/42
3) 2 целых 7/18 17/42 = 43/1817/42= 731/756

(4 + 2 7/15) * (10 - 8 16/23)=5 целых 56/345
1) (4 + 2 7/15)= 6 целых 7/15
2) (10 - 8 16/23)=9 целых 23/23 - 8 целых 16/23=1 целая 7/23
3) 6 целых 7/15 - 1 целая 7/23 = 5 целых (161-105)/345 = 5 целых 56/345

(4 + 5 1/6) * ( 3 2/3 - 13/33)=30
1) (4 + 5 1/6) = 9 целых 1/6
2) ( 3 2/3 - 13/33) = 3 целых 22/33 - 13/33 = 3 целых 9/33 = 3 целых 3/11
3) 9 целых 1/6 3 целых 3/11 = 55/6 36/11 = 5 6 = 30

6 5/12 * 4/11 - 11 4/11 * 1/9=1 целая 7/99
1) 6 целых 5/12 4/11 = 77/12 4/11 = 7/3 1/1 = 7/3 = 2 целых 1/3
2) 11 целых 4/11 1/9 = 125/11 1/9 = 125/99 = 1 целая 26/99
3) 2 целых 1/3 - 1 целая 26/99 = 2 целых 33/99 - 1 целая 26/99 = 1 целая 7/99