12/9: 3 2/3+4 2/5: (7/10+2 3//17-1 16/17: 11) 5/6+2 3/4: 4 8/9×2 2/3-1 2/3+(5/38×1 2/3-10/57)

1 2/9:3 2/3+4 2/5:(7/10+2 3/5)-(3/17-1 16/17:11)=

(1•9+2)/9: (3•3+2)/3+ (4•5+2)/5: ( 7/10+ 2 (3•2)/(5•2)) - ( 3/17- (1•17+16)/17 • 1/11)=

11/9: 11/3+ 22/5: ( 7/10+ 2 6/10)- (3/17- 33/17• 1/11)=

Сокращаем 33 и 11 на 11;

11/9• 3/11+ 22/5: (2 13/10) - (3/17- 3/17• 1/1)=

Сокращаем 11 и 11 на 11; 9 и 3 на 3;

1/3• 1/1+ 22/5: (2•10+13)/10 -0=

1/3+ 22/5: 33/10=

1/3+ 22/5• 10/33=

Сокращаем 22 и 33 на 11; 5 и 10 на 5;

1/3+ 2/1• 2/3= 1/3+ 4/3=

5/3= 1 2/3. ответ

5/6+2 3/4:4 8/9×2 2/3-1 2/3+(5/38×1 2/3-10/57)=

5/6+ (2•4+3)/4 : (4•9+8)/9 • (2•3+2)/3 - (1•3+2)/3 + (5/38• (1•3+2)/3 - 10/57) =

5/6+ 11/4: 44/9• 8/3- 5/3+ (5/38• 5/3- 10/57)=

5/6+ 11/4• 9/44• 8/3- 5/3+ ( 25/114 - 10/57)=

Сокращаем 11 и 44 на 11; 4 и 8 на 4; 9 и 3 на 3;

5/6+ 1/1• 3/4• 2/1- 5/3+ (25/114- (10•2)/(57•2))=

5/6+ 6/4- 5/3+ (25/114- 20/114)=
Сокращаем 6/4 на 2;

5/6+ 3/2- 5/3+ 5/114=

5/6+ (3•3)/(2•3) - (5•2)/(3•2)+ 5/114=

5/6+ 9/6- 10/6+ 5/114=

4/6+ 5/114=
Сокращаем 4/6 на 2;

2/3+ 5/114= (2•38)/(3•38)+ 5/114=

76/114+ 5/114= 81/114=

Сокращаем на 3;
27/38. ответ.