DESCRIPTION: The Trinomial cube comes in after the child is introduced to the Binomial cube. This again is a perfectly fitting example of a child’s learning in concrete before going for abstract concepts. The trinomial cube is a concrete representation of the algebraic formula (a +b +c)3.The trinomial cube is contained in a wooden box with a lid, having two adjacent hinged sides that open out to display the 27 wooden component cubes and prisms painted red, blue, yellow, and black. The factors of the equation are represented by the cubes and prisms. The child uses it for sensorial exploration, while the elementary child uses the trinomial cube as a concrete step towards algebraic expressions.