The conversation between human and AI assistant.
[|Human|] Create a mathematical expression to calculate surface area of a cube.
[|AI|] The formula for calculating the surface area of a cube is `6 * (edge_length ** 2)`, where `edge_length` is the length of one side of the cube. This formula represents the sum of the area of all six faces of the cube; every face of a cube is a square.
[|Human|] 
Create a mathematical expression to calculate surface area of a cube.