Mix blue and yellow paint together and discover that they make green.
You already turned red and yellow into orange. Today you try two new colors: blue and yellow.
Mix a little blue with a little yellow. Watch closely. What new color shows up this time?
Mastery looks like: They predict and correctly name green as the result of mixing blue and yellow.
Common stumbles: Mixing in leftover red from the palette by accident, muddying the green.