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