[English Translation of H. Barendregt's press release] World Championship of Exact Arithmetic Nijmegen, 4 October 2005 In the Department of computer Science of the Radboud University on 3 and 4 October an international competition was held for calculating mathematical quantities with an arbitrarily given degree of accuracy. There were 9 participating teams and two classes of problems were posed. The winners were in the basic problems the team of Wolfram Research (USA), known for their computer program Mathematica, and in the intermediate problems a team working at the academic institute LORIA (France). Numbers such as Pi=3.141... have infinitely many digits after the decimal point without a periodic pattern, unlike the case with 22/7=3,142857142857142857... and all other fractions of integers. Throughout the ages it was considered as a sport to find more and more digits after the decimal point of such numbers. Around the year 1600 Ludolph van Ceulen, after many years of work, calculated Pi=3,1415926535897932384626433832795..., correct up to 31 digits. Around 1670 Newton could calculate that Pi=3,1415926535897928... where he could use the help of his just developed new mathematics (differential and integral calculus). For that, Newton needed only one afternoon. However, he did make a mistake in the last two decimals `28' (it should be:`32'), while van Ceulen had verified all his obtained decimals. Later, in the 20th century computers have accurately calculated Pi up to many billions of digits. Also in the 21st century this sport is still being practised, not with a chosen number such as Pi but with arbitrary mathematical expressions. The international competition between the computer programs that was held in Nijmegen in 3 and 4 October, was organised by Milad Niqui and Freek Wiedijk and its aim was to correctly calculate a number of mathematical expressions in 1,000,000 and more digits as fast as possible. In the basic problems there were expressions such as sin(tan(cos 1)) and in the intermediate problems x_1000000, where x_0=0,5 and x_{n+1}= 3,999 x_n(1-x_n). There is the question why this sport is of any use. There is a good mathematical tradition that prevents the rounding errors in the accumulated calculations from getting out of hand. In order to calculate a number in 14 digits after the decimal point, sometimes one needs more and more digits for the intermediate results. This is related to the well-known butterfly in Brazil from Chaos Theory, which by moving his wings can cause a storm in Europe. It is actually possible to work with an arbitrary precision where the number of decimal digits can be freely chosen. In principal, this can cause a compromise in the speed. The competition has shown that for calculating a typical set of mathematical expressions one doesn't have to sacrifice precision for speed. For the problems and results see .