Description: in a hinged wooden box, the binomial cube is the geometric representation of the formula (a+b)3. It's made up of 2 cubes and 6 prisms representing the factors of the equation, the child's first steps in algebraic exploration. The lid of the box represents (a+b)2 because it's in the plane and not in volume like the cube.
Direct aim: visual discrimination of colors and dimensions.
