If you consider yourself intelligent, and you consider yourself civilized, the rudiments of real numbers is not beyond you.
We communicate colour data as three quantities between 0 and 1. The order differs according to the standard: sometimes (R,G,B), sometimes (B,G,R).
Importantly, the value of Red is the complement of the value of Cyan : R = 1 - C; and similarly for the other primaries. In other words, if we have an RGB colour value of (1,0,0), we will print the CMY (0,1,1).
Now, it is a fact of printing that adding the three printing primaries does not produce a true black: black ink is required. Using the simple formula given, the RGB value (0,0,0), will be printed as CMY (1,1,1).
But the simple formula is an oversimplification. Development of the printer will be in conjunction with a colour-matching algorithm.
And similar adjustments will need to be made for scanners.
It must be realized, however, that the simple formula given is a great oversimplification. Due to different printing processes, inks, and the varying luminance of emission primaries, (R,G,B) must be mapped to (C,M,Y,K) through a colour profile.
Development of the printer and the algorithm will be at a significant cost; and we will no doubt want to develop a scanner at the same time, to refine our calculations beyond the capabilities of our eyesight.
But here's a thought: if a scanner can produce CMYK data, why, for the love of God, do printers not do the same thing when passed RGB data?
Why must artists control the black?