The document discusses differentiation and finding the derivative of functions. It begins with lesson objectives of understanding how differentiation can be used to find the gradient of a curve and learning the basic rules of differentiation. It then defines differentiation as finding the gradient function, also called the derivative. Several examples are provided to illustrate the pattern for finding the derivative of functions like x^2, x^3, etc. The basic rules of differentiation are outlined, including how to take the derivative of sums and constant functions. Students are then instructed to practice applying these rules through examples.