Classic "Yellow Area Material" from Montessori Elementary, helps teach concept of area as measured by identical squares on rectangle. Once that is mastered, this material shows how other shapes with equivalent areas can be converted into rectangles, eventually leading to algebraic notation (A = BH, A = BH/2).RectangleParallelogramRight TriangleAcute TriangleObtuse triangles. Print BW on cardstock (use yellow paper for classic look), or glue paper to cardboard. Cut along dashed lines (NOT solid l