48 3/5: 6 3/4 •5/12- 2 5/6 +13 2/9 • (1 1/2 • 1 1/3 - 13: 26)= 20.
1)) скобка (1 1/2• 1 1/3- 13: 26)
по частям
1 1/2• 1 1/3 = (2•1+1)/2 • (3•1+1)/3= 3/2• 4/3 = 1/2• 4/1 = 1/1• 2/1 = 2.
{сократили, значит поделили 3 и 3 на 3; 4 и 2 на 2}.
13:26 = 13/1• 1/26 = 1/1• 1/2 = 1/2;
{13 и 26 сократили на 13};
2- 1/2 = 2/1- 1/2 = (2•2)/(1•2) -1/2= 4/2 -1/2 = 3/2 = 1 1/2.
Скобка = 1 1/2.
2)) 13 2/9• скобку= 13 2/9 • 1 1/2= (9•13+2)/9 • (2•1+1)/2= 119/9 • 3/2= 119/3 • 1/2= 119/6= 19 5/6.
{сократили 9 и 3 на 3}.
3)) 48 3/5 : 6 3/4 = (5•48+3)/5 : (4•6+3)/4 = 243/5 : 27/4 = 243/5 • 4/27 = 9/5 • 4/1 =
36/5 = 7 1/5;
{сократили 243 и 27 на 27};
4)) 7 1/5 • 5/12= 36/5 • 5/12= 36/1 • 1/12= 3/1• 1/1= 3.
{сократили 5 и 5 на 5; 36 и 12 на 12}.
5)) 3 - 2 5/6= 3-2 -5/6= 1 -5/6=
(1•6)/1•6) - 5/6 = 6/6 - 5/6= 1/6;
6)) 1/6+ (2действие)= 1/6+ 19 5/6= 1/6+ 19+ 5/6= 19+ 6/6= 20.
Ответ: 20.