Вычислите: (3/4+1/5)*5/19= (12 1/3-7 3/4)*6/11=

(3/4 + 1/5) * 5/19 = 1/4
1) 3/4 + 1/5 = 15/20 + 4/20 = 19/20;
2) 19/20 * 5/19 = 5/10 = 1/4 = 0,25

(12 1/3 - 7 3/4) * 6/11 = 2 1/2
1) 12 1/3 - 7 3/4 = (12 - 7) + (1/3 - 3/4) = 5 + (4/12 - 9/12) = 5 - 5/12 = 4 7/12  
2) 4 7/12 * 6/11 = 55/12 * 6/11 = 5/2 = 2 1/2 = 2,5