The possible colors are blue, yellow, white, red, orange, and green. How many four-color codes can be made if the colors cannot be repeated? To some degree, this whole paragraph in the beginning doesn't even matter. If we're just choosing from how many colors are there? There's one, two, three, four, five, six colors. And we're going to pick four of them. How many four-color codes can be made if the colors cannot be repeated?