Limits are intuitive, yet elusive. Learn what they are all about and how to find limits of functions from graphs or tables of values. Learn about the difference between one-sided and two-sided limits and how they relate to each other.
Learn one-sided and two-sided limits. Investigate the relationship between a two-sided limit at a point and the one-sided limits at that point (spoiler: the two-sided limits exists if and only if the one-sided limits exist and are equal).
Now that you have an intuitive understanding of limits, let's do what mathematicians do best and define them rigorously! This definition may be hard to grasp at first, but its beauty will get you in the end.