There is no explicit mechanism, such as float(integer), in the Korn Shell (ksh93) to convert an integer to a float which in the Korn Shell is by default a long double.
By default, dividing integer 1 by 3 produces 0:
$ integer x=1 $ echo $(( x/3 )) 0 $
So how to you get the result, 0.3333 …, which you probably were expecting?
You can convert x to floating point and then do the division by replacing the 3 with either 3. or, as I normally do, with 3.0:
$ integer x=1 $ echo $(( x/3. )) 0.333333333333333333 $
Note the Bash shell does not support floating point so this will not work with Bash.