A recursive function is a function that calls itself in order to solve a problem. This approach allows complex problems to be broken down into smaller, more manageable sub-problems. Each time the function calls itself, it works on a simpler version of the original problem until it reaches a base case, which is a condition that stops the recursion. For example, calculating the factorial of a number can be done using a recursive function. The factorial of a number n is defined as n multiplied by the factorial of n-1, with the base case being that the factorial of 0 is 1. This method simplifies the calculation and makes the code easier to read.