if you want to learn more about nodes search out all of BagginsBill threads (here and at  err I forgot the other site he lives in!! some one else will know)

maths node has value 1 = A value 2 = B and the output is C so not sure what your asking

colours use a "tuple" (RGB where each part is a number from 0 to 1) some nodes average out the 3 I think where others use vector math (I might be wrong on that 'cos I dont use poser much nowadays)

 

hope that helps a little