Abstract: An educational aid for teaching the concept of primary factors of numbers, multiplication, division, facturing and the like, based on the isomorphic adaptation of basic colors to primary numbers each being represented by a certain basic color and composite numbers by fields of color being obtained by mixing the corresponding basic colors in unit quantities according to the factors making up said composite number, so that given a certain field of color corresponding to a composite number, the student can match said field by the correct mixture of said basic colors and thereby find the factors of the number represented by said field, or conversely the student can mix certain basic colors in unit quantities and match the resulting color with a field of color and thereby learn multiplication. The number 1 is represented by a colorless transparent material, and the number 0 by a piece of opaque black material.