Potassium ions move out of the cell and the electrical potential becomes more negative.
The current is created in a way that allows it to move away from the place that it originated, and therefore allows the cell to influence other cells that are far away. It wouldn't be completely honest to say that you can't get some understanding of these questions without completely understanding the mathematics involved, but by understanding the mathematics, you can gain a deeper, more reliable understanding. After all, mathematics is just the process of making your understandings of the relationships between things more precise and self-consistent. Principles of Neural Science.