Cuisenaire Rods   We use the Cuisenaire-Gattenio rod system:   Each rod in this system has two attributes: length and color. It should be noted that the colors of the rods have no quantitative meaning (e.g. the purple color is not bigger than the red color) and that the choice of color for each rod length was made arbitrarily. The role of the color is to facilitate the distinction among the rods, and like the symbol, it is intended for easy recognition and communication. For example, the color of the rod representing the number 5 is yellow, but it could just as well have been any other color. It should be stressed that we call the rod by its corresponding number, not by its color, and thus say "the 5 rod" and not "the yellow rod."