1/8, slightly.
No.
15.337
15.337
As compared to converting decimal into what other base! It is no more difficult to convert decimal into base 8 than decimal into binary or Hex.
1.334
To get the decimal, divide the numerator of the fraction by the denominator. If the decimal runs to more than one place, then you have to round it to one decimal place.
147.3
There are eight movies as the last book was released in two parts. There will not be any more books or movies.
It is now then 15.337 when 1/10 or 0.1 is added to it
The answer depends on what the comparison is with! It is not more difficult than proving the Goldbach conjecture, for example.
To the first decimal would be 23.6 (anything more than 23.50 would go to the next tenth).
Whether or not it is difficult depends on your aptitude and your attitude. What you may find difficult I might find easy and conversely.