L=(QuantityUnit[3994.485])
FSR=((QuantityUnit[1])/(2L))~UnitConvert~"Hertz"
(Subscript[f, mod])=(QuantityUnit[24.407079])
r=((Subscript[f, mod])/FSR)
int=IntegerPart[r]
frac1=FractionalPart[r]
frac2=1-frac1

Print["Cavity Length = ", L]
Print["Free-spectral-range = ", FSR]
Print["Modulation frequency = ", (Subscript[f, mod])]
Print["\!\(\*FractionBox[\(Modulation\\ frequency\), \(FSR\)]\) = ",r]
Print["Integer part = ",int]
Print["Fractional parts = ",frac1, " and ",frac2]