Montessori sensory teaching aids binomial and trinomial, suitable for children over 3 years old Develop children's visual ability, build cube wood blocks, and make children understand more easily through intuitive display Prepare for the binomial and trinomial learning of mathematics and cultivate the ability of thinking in Mathematics Lay the foundation for the study of square root and prepare for the mathematical algebra of senior students High quality wood, no smell, no burr, protect baby's hands Product Description: 1. Binomial: a wooden box with a cover, with 8 cubes in it, presenting the equation: (a+b)³=a³+3a²b+3ab²+b³, the box cover presents the pattern in the form of a plane. 2. Trinomial formula: a wooden box with a cover, containing 27 small cubes, showing the equation: （a+b+c）³=a³+b³+c³+3a²b+3ab²+3b²c+3bc²+3a²c+3ac²+6abc. 3. Develop children's cognition and understanding of three-dimensional space, prepare children to learn algebra binomial and trinomial, cultivate children's mathematical thinking ability, and improve children's ability to solve problems. 4. Scenario: suitable for families, kindergartens, early childhood centers, nurseries, parent-child kindergartens and other early childhood institution