system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does calculator know and use pi if even super computers can't know all the digits. Does it use like first 100 digits?
gpt
Probably way less than that. For any real-world application, even a few decimal places are totally sufficient. Use 6 digits, and the circumference of a kilometer-wide circle is less than a centimeter off the true value. That's already better than most measurement methods. And additionally to that, computers in general can't handle infinitely precise numbers.

If you do the right calculations, the error could stack up, but in this case you rather use mathematical tricks to simplify the calculations first, before using any hard-coded numbers.