Regarding scheme languages

[kavi]

( I kept option as professional language
(Graphical (MrEd, includes MrScheme))

I gave an input as rational number and the output i am getting the
same.
example
Input =(1/2)
the output i am getting = (1/2)
but i want an output as floating point (0.5).
Is there any syntax to get a floating point number.

(But when i choosed option as Beginning Student)

I got a the answer what i expected as floating number.
But now i want the number to be rational number.
example
input = (2/4)
the output i am getting= (0.5)
i want the output to be as (2/4)
Is there any syntax to get a output as rational number (1/2).