I started my independent learning by solving the max box problem given by my personal tutor (see Appendix A). This problem about the paper which has side a, then I was instructed to make a box by cutting a square with side x from each of the four corners. I have to find the value of x so that I can make the biggest box. I tried to find the x value for creating the biggest box by doing some algebraic equations and finally, I obtained the pattern for finding the x value. Finding out the answer gave me an opportunity to relate it to the concept of differentiation. It was a new thing for me and when I searched on the internet, found it was popular in teaching and learning mathematics related to the calculus topic. However, I did not know why I found Indonesian mathematics teachers rarely used this practical question while teaching the concept of differentiation.Next, I moved to how to introduce the first principle of differentiation, f'(x), from function f(x). I started by drawing a graph of the function, then formulated gradient of two adjacent points using the gradient of a straight line and limit concept (see Appendix B). Finally, I found that the first derivative equals with the gradients of a point from the function. Then, I tried similar calculations for some different functions, and finally, I established the pattern of the first derivative. While doing this, I was thinking which I should teach first, gradient or differentiation, in order to make students understand where the first derivative comes. Furthermore, a noticeable point for me by solving this problem, I was aware that as a teacher I can teach mathematics through using algorithmic/algebraic/analytic/calculating, visual (image/graph), and inductive (pattern) thinking. For example, when finding the maximum value of the function, I acquired the same answer by using two different methods, graphing and calculating.