The formula turns an infinite sum into a more manageable calculation of single terms

Yahoo!'s Tsz Wo (Nicholas) Sze has gone further in computing specific bits of ? (pi), the mathematical constant, than anyone else in the world. He has calculated the 2,000,000,000,000,000th digit of the mathematical constant pi - and a few digits either side of it.

"So, we now know: The Two Quadrillionth Bit of ? is 0! Yes, you read that right; "Two Quadrillionth." Wow."

Sze used Yahoo's Hadoop cloud computing technology to more than double the previous record. It took 23 days on 1,000 of Yahoo's computers - on a standard PC, the calculation would have taken 500 years.

The heart of the calculation made use of an approach called MapReduce originally developed by Google that divides up big problems into smaller sub-problems, combining the answers to solve otherwise intractable mathematical challenges.