I-2 1/6I:I4 1/3I = 2 1/6 : 4 1/3 = 13/6 : 13/3 = 13/6 * 3/13 = 1/2
I5,7I * I-2 2/19I = 5,7 * 2 2/19 = 57/10 * 40/19 = 12
I-9 3/7I * I7/11I + I-2,9I = 9 3/7 * 7/11 + 2,9 = 66/7 * 7/11 + 2,9 = 6 + 2,9 = 8,9
I-6,2I : I0,2I - I-7,4I = 6,2 : 0,2 - 7,4 = 31 - 7,4=23,6