OK, I threw you a green.
Proceeding with our experiments we fill out the additive color- mixing chart as follows:
Green + red = yellow
Green + blue = cyan (light blue)
Red + blue = magenta
Red + blue + green = white
Subtractive colors, as the name suggests, work by subtracting certain colors from white light and reflecting the rest, like so:
Yellow pigment absorbs blue--reflects red, green
Cyan absorbs red--reflects green, blue
Magenta absorbs green--reflects red, blue
Blue absorbs red, green--reflects blue
Red absorbs blue, green--reflects red
Green absorbs blue, red--reflects green
If white light strikes yellow paint, the paint absorbs blue and reflects red and green. Then the additive principle takes over--red and green combine to make yellow.
Now mix cyan (light blue) and yellow paint. The cyan pigment absorbs red light; the yellow pigment absorbs blue light. What's left is green, the color you see.
Any questions?