Around 480 AD, Zu Chongzhi, a mathematician in the Northern and Southern Dynasties, further got the result accurate to 7 decimal places, which was simplified to 3. 14 15926.

17 At the beginning of the 5th century, the Arabic mathematician Cassie got the exact decimal value of pi17, which broke the record kept by Zu Chongzhi for nearly a thousand years. German mathematician Ludolph van ceulen calculated π to 20 digits after the decimal point of 1596, and then spent his whole life calculating π to 35 digits after the decimal point of 16 10.

Extended data

Pi has been an enduring topic since it was recorded in writing. Cantor, a German historian of mathematics, once said: "The accuracy of calculating pi in a country in history can be used as an indicator to measure the level of mathematical development in this country at that time."

Pi is an irrational number, that is, an infinite cycle decimal. In daily life, pi is usually expressed as 3. 14, which is used for approximate calculation. The fractional part 3. 14 1592654 is enough for general calculation. Even if engineers or physicists want to make more accurate calculations, they only need to take the values to a few hundred decimal places at best.

The first person who used only one letter to express pi was storm, a professor of mathematics at Orff University in Bavaria, but he used e instead of π. He used e to represent pi in 1689.

In a book published in 1706, the British mathematician william jones expressed pi for the first time. However, his practice did not get people's response immediately. It was not until 1748 that it was gradually accepted by people under the strong advocacy of German mathematician Goldbach and others.

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