If you are like me then you have to assess your four year old students' ability to sequence red rods from shortest to longest. I find that seriation is a difficult skill for my students to master so I teach it from the beginning of the year in ways that I think are more meaningful to my students than rods of different lengths. We start off by putting several classmates in order from shortest to tallest. We move on to using pictures that relate to the current theme of study. Eventually the kids progress to using the red rods. This activity includes 3 sets of Christmas pictures for the kids to sequence: candy canes, Christmas trees, and gingerbread men.