the rope is 1 and 1/3 long,
1 is the same as saying 3/3,
this means that the rope is 3/3 + 1/3 long,
so it is 4/3 foot long,
you now want to get half of this number so that each person has an equal length of rope,
so multiply the length of rope by a half,
4/3 x 1/2 = 4/6 , which if simplified = 2/3,
this means that each friend gets 2/3 foot of rope.
You can draw this in a diagram by drawing the 1 foot of rope, and then dividing it up into 3 sections. Then add the 1/3 foot of rope into the drawing. It should then be easy to see that altogether there are 4 separate sections of rope and that if each friend has two sections then they will be sharing equal amounts, so consequently each friend has two of the thirds of rope, i.e. 2/3