I always find that kids have trouble learning the concept of "shades of colors." They think each color means one thing and are always amazed to learn there is light blue, dark blue, royal blue, etc. And they are all "blue!" To help kids practice identifying different shades of the same color, I created some fun shades of colors worksheets.
matching colors memory games! Check those out too! Each game has 16 cards (8 matching sets) so you can play them individually or play all 32 cards at once for a really memory challenge.