It's pretty simple, the things you need to know first:
The fraction are fraction of a inch, so 1/4 in decimal is .250, (4/4 = 1/1 = 1.000)
There is 12" in a foot.
So you have 23 foot + 6" + 6" + 7/8"
So it made 23 foot + 1 foot + 7/8"
The final result is 24' 7/8"
