I always get lost in the detail when learning or working on math, and I find that new math concept introduced only a few important concepts. The rest are filling in details by connecting new and old concepts in the right order using math notation. Think of new math concepts as tools that are reusable for tasks in which tools are specialized for. In this series of “Explaining X” where X is any mathematical concept, I will try to avoid mathematical details and will try my best to capture the newly introduced concept.