Using a paper plate, write the numbers 1 - 12 like a face of a clock. Put the three primary colors on first, 12:00 is red, 4:00 is yellow and 8:00 is blue. For the secondary colors mix the primary colors as you go around the clock. At 2:00 mix red and yellow for orange, 6:00 mix yellow and blue for green and 10:00 mix blue and red for purple. For the tertiary colors mix one primary color and the secondary color next to it. At 1:00 mix red and orange, at 3:00 mix orange and yellow and so on around the wheel. This is a really easy way for the kids, well for me as an adult too, to see the relationship between the colors and remember the combinations.