What does the pixel value mean for a RGB or CMYK image? [closed]

I am using matlab to convert RGB image to CMYK ,The first pixel value was in RGB and CMYK images as follows : Red=22,Green=32,Blue=42 . Cyan=167,Magenta=130,Yellow=95,Black=199. But when I used mathematical equations to calculate the cyan value as follows : R'=22/255=0.086, G'=G/255=32/255=0.125 B'=B/255=42/255=0.165 K = 1-max(R', G', B ') =1-max(0.086,0.125,0.165 ) =1-0.165 =0.835 C = (1-R'-K) / (1-K ) =(1-0.086-0.835)/(1-0.835 ) =-0.079/0.165 =0.479 But the cyan value for the first pixel was 167 , and the calculated value was 0.479 .So what is the difference between these two values?