1) (3/4+1/5) * 5/19

2) (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 = 5/20 = 1/4 = 0,25

(12 1/3 - 7 3/4) * 6/11 = 2 1/2

1) 12 1/3 - 7 3/4 = 12 4/12 - 7 9/12 = 11 16/12 - 7 9/12 = 4 7/12

2) 4 7/12 * 6/11 = 55/12 * 6/11 = 5/2 = 2 1/2 = 2,5