# When will we find out if pi is normal?

21 October 2012

## Question

When will we find out if pi is normal?

Matt - That is a very good question because at the moment, we don't know whether or not pi is normal. Normal has a very specific definition in maths, so if we say a number is normal, it means that any string of digits is equally likely to appear in its decimal expansion. And so, the decimal places of pi go on forever and they never repeat, but we don't know effectively how well distributed they are if you go far enough down. And we've checked trillions and trillions of digits and it's been normal all the way so far. But we can't guarantee that it will continue to be normal after that. And so, I suspect it's going to be a while because currently don't have any really good mathematical techniques to explore that far into pi or to find some way to pin down to show why it is or it isn't normal. But hopefully one day, people will develop some new mathematical ideas and will be able to answer that question.