Does this one of these three numbers correspond to our intuitive notion of "brightness", i.e. dull red vs bright red? I'm thinking chroma but not sure.
I believe value corresponds how dull or bright a color is (up/down in the image). Chroma seems to be associated with saturation (left/right in the image).
If anyone wants to try their hand at distinguishing and sorting these colors, there's a great (free) game on the app store that turns swatches like these into cool puzzles! It's called Blendoku. Check it out!