If a number like Pi is infinite, how do we know each decimal that is newly calculated is valid?

Question

Not a mathematician here at all so perhaps my question is phrased incorrectly.

Let’s say through thorough testing in reality, we can prove with certainty Pi is correct up until 5 decimal places,

3.14159

The computers that are calculating Pi to an endless degree, how do they validate new values that are calculated as correct and cannot be otherwise?

In: 434

Answer 1

It seems no one has addressed the obvious, which is that the question from the get-go is wrong: **Pi is not infinite.** Pi is a finite number, somewhere between 3 and 4, but has an infinite number of digits in its decimal representation.