Jonathan Botha

Computer Scientist

Coder

Web Designer

Jonathan Botha

Computer Scientist

Coder

Web Designer

Blog Post

Memorising π

March 17, 2020 Education
Memorising π

3.14159265358979323846264338327950288419716…

This year was the first year I celebrated Pi Day; and boy was it interesting! Oddly enough though, for me the celebrations began on the 13 March when a friend caught my attention. I was on my way to invigilate a test when I was called over to the Mathematics building where some people were creating hype for the upcoming Pi Day. They had a range of activities available to demonstrate the usefulness of pi, and also a few competitions. From these competitions there was one that peaked my interest: “How many digits of pi can you memorise?”.

I, for one, have never attempted to memorise any digits of pi for fun, but in the moment I thought, “How hard could it be?” I went into the competition expecting to need ~20 digits of pi and when I looked at those who signed up so far they had gone well over 30!

The mnuenomic rhyme

There were multiple rounds which you could enter and I quickly tried to start learning pi. The trick I wanted to use was to use some form of algorithm to calculate a limited number of digits of pi, but it appears this isn’t a popular approach. What is popular is songs and sentences that can help you remember the digits. I set off immediately trying to remember a poem that contained 31 digits of pi:

Now I will a rhyme construct,
By chosen words the young instruct.
Cunningly devised endeavour,
Con it and remember ever.
Widths in circle here you see,
Sketched out in strange obscurity.

The trick here is to remember the rhyme and count the letters in each word. If you do this you will have 31 digits of pi memorised! However, me being a number person before a word person, I struggled to remember most of the passage before the current round ended and often slipped up the counting of letters. This method was great for remembering the digits of pi, but took too long for regurgitation. Within the short time span of 15 minutes, I memorised most of the poem, but slipped up so much in converting text to numbers that I only got a score of 4 before the time ran out.

Using my strengths

I then left to go to the test venue, but by this time I was already determined to do better. I got a pen and paper and started out on my own way to remember the mathematical constant. However, this time instead of remembering words I focused on my love for patterns.

Patterns appear all around us and sometimes even appear in simple places such as license plates. I love looking at license plates and seeing “Oh, ‘8421327’ is halving 8 until 1, then adding the last 2 numbers and putting the result to the power of itself.” This may seem obscure, but I have found many people who use such techniques to remember numbers – even if they are not exactly as above.

Long story short, I was able to memorise a whopping 37 digits of pi within 30 minutes. For me this was an incredible feat as I had never tried this before and from zero went well above my initial expectations. I submitted my score, but shortly after someone wrote down 100 digits from memory! I will say there are some crazy people in this world, but (even though I didn’t win the mug I yearned for) I had fun.

Conclusion

Looking back over all that happened I realised that you will find that every person has their own way of remembering useless information. No two people are the same and in the end its about finding out what works for you. If you don’t know what works for you then try to memorising the digits of pi, you might just surprise yourself.

My method

I am sure some of you might wonder what my method was, but as a disclaimer I will warn you that it is very obscure.

3.141Everyone should know this part
5sum of the last 2 digits and will surround the next 2 groups.
926A transformation of 9 by flipping
5The grouping number
39-6-3 is the pattern before
5The grouping number
8Sum of the last 2
979 323A group transformation. The 9’s get rooted, and the 7 transforms into a 2. (Everything gets smaller)
462648 and a nice big palindrome. Binary numbers from 8 to 2 then up.
8 is the only even not in the palindrome.
3383From the previous 4 I remembered double 3 and doubled 4 then had an extra 3. It just worked for me somehow.
279Cube the last digit and then get the middle power.
50Is a nice number and the section end.
28841Saying it fast helped remember it (288 for 1)
9716I remembered the date 1697. (This is where is made my mistake and ended with 37 digits)
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