A brief look at two methods of combing colors - additive color, which uses red, green and blue as primaries, and so-called 'subtractive' color, which uses cyan, magenta and yellow.
Additive color describes the way colored light combines.
'Subtractive' color describes the way colored filters stack up, or the way certain pigments mix.
We usually teach children the 'subtractive' method, which uses cyan, magenta and yellow, first. We often simplify and approximate magenta as 'red' and cyan as 'blue,' so most school children think the paint primaries are red, yellow and blue.
Why do I keep putting the word 'subtractive' in quotes? Watch the clip and you'll know in 3 minutes from now.
There are actually two kinds of 'subtractive' color mixing. One, described above, is multiplicative. The other, described here, is closer to averaging.