Knowing 169 decimals of pi by heart: how to do it?
How many decimal places of π (pi) do you know by heart? That was the question during a special competition on pi day last week in the central hall of the Gorlaeus. The winner of the competition managed to recite 169 digits after the comma. Jonathan Love reveals his secret.
That Jonathan Love is into numbers is the understatement of the year. The postdoc studies number theory and started memorising and reciting numbers of pi at a young age. 'I could remember 200 when I was 13. It's been years since I last recited them, but I wanted to give it another go to see how many I still knew.'
What’s your secret?
‘There’s a song that recites the numbers, and I listened to it over and over to memorise it. That song inspired me to remember the digits. It’s easier to memorise them if there's a tune attached to it.’
What’s the point of knowing this?
‘There's not really any point. In practice, you don’t need to memorise digits of pi – even 3.14 is more than enough when you’ve got calculators and the internet. Memorising numbers is more like a game of solitaire. It’s just one of the many ways to pass the time and try to beat your personal best score.’
Were you happy with your score?
‘I was just happy to see how many digits I could still remember after so many years.’
Will you be taking part again next year?
‘Probably not - I've set a level to beat and encourage others to step up to the challenge!’
π? Pi? 3.14? How does it work again?
If you divide the circumference of a circle by its diameter, you always get the same value, namely 3.14. This 3.14 is called pi. This number is a constant, meaning it always has the same value. Pi is used for calculations involving circles. For example, the circumference of a circle is: pi * diameter, and the area is pi * radius².
We usually write pi as 3.14, but actually, the number is infinite. The digits after the decimal point continue endlessly. Most people stick with 3.14, but for accurate calculations, more decimal places are needed. There are now over 1,241,100,000,000 known decimal places.
Did you know?
- The mathematical symbol for pi is π: the small letter p from the Greek alphabet.
- We celebrate Pi Day on the fourteenth day of the third month because 3, 1, and 4 are the first three digits of pi.
- In the American date format (year/month/day), this corresponds to 14 March.