A single cell amidst a million other cells in a typical worksheet looks as if it can only do a single action at a time? For example, display text or some numbers or maybe calculate a formula. What most people don't realize is that many things can take place in a single cell simultaneously.
Here is a visual illustration of what you can enter in a single cell at the same time. Excel is amazing.
A video tutorial on this topic is also available on the 'Free Resources' page.