system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:  How do we know that there is an infinite number of digits in pi?  Is it possible that it's actually just a really big but finite number?
gpt
Truth be told, pi isn't big at all. Pi is approximately 3 (3,141592...), it's just impossible to display exactly. Any approximation you make, will necessarily be off by a little bit.

So, let's see. Let's fill the circle with a square size 2. Then we've still got 4 parts left, so let's try and fill those up with squares. As you may be able to see, this will never fill up. A similar thing happens to pi, no matter how many digits you list, you never "fill up" the number.