How can get green color from blue and yellow in GIMP?

[imager]

It is said that blue + yellow = green.  
In GIMP, create new layer with blue color and add new layer with yellow,merge them ,the color don't turn to green,it is yellow.

How can get green color from blue and yellow in GIMP?

My merge way,what is the right merge way?

[rich2005]

Same question on Gimp chat. https://gimpchat.com/viewtopic.php?f=8&t=21792 There is no red in blue