system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do computers choose "random" numbers?
gpt
You start with a sort-of-random number. Often something like "the number of milliseconds since January 1st 1970" is close enough to random to count, but if you want to be really random, you base it off of something like whatever random noise the computer's microphone picks up or the airflow readings around the hard drive. Then you put that number through some super messy and complicated math formula to get an even more random number. Then you can feed that number back into the same calculation to get another number. These numbers aren't truly random, but it's close enough for almost all purposes.