I think there is also a gotcha there as you get a ratio in Common Lisp and not a floating point number.
> (print (format t "1 divided by 2 is ~a and its type is ~a" (/ 1 2) (type-of (/ 1 2))))
> 1 divided by 2 is 1/2 and its type is RATIO
I don't think there is a simple solution. Numbers are harder than they seem and you just need to know what happens in the particular language you are programming in.
Neither Java nor CL were intended for the novice; I'm sure Mr. Steele had Scheme in mind.