How to remember 100 digits of Pi, easily
I know, this is a completely worthless thing to memorize. Even NASA uses a mere 15 digits of Pi for their highest precision calculations, and according to them, just 38 digits of Pi are sufficient to calculate the circumference of the entire observable universe to an accuracy equal to the diameter of a hydrogen atom. But hear me out, this is a trick that's worth learning if you want to impress your friends, especially considering how easy it is to learn!
The technique is a standard method used by professional memory champions. So if you learn it for this trick, you can use it for many other use cases, like memorizing phone numbers and even the order of a shuffled deck of cards. It's called "major system". This allows you to map each digit into a distinct sound and construct mnemonics that are easy to remember. See the table below:
|6||j, sh, ch, soft g|
|7||k, hard g, hard c|
|8||f, v, ph|
|0||z, s, soft c|
Lets look at an example. Say you want to remember the number 42. Since it maps to [r, n], you can choose any word that has these consonant sounds like rain, run, or ruin. Similarly, 620 could be jeans, Jonas, or chains. An important property of this system is that although a number can be converted into many words, a word can be translated only into a single number.
Now lets get to the good stuff. Try to remember the following sentence:
My turtle Pancho will, my love, pick up my new mover, Ginger.
Done? Congratulations, you now know the first twenty-four digits of Pi! Here's how it works. If you map the consonant sounds in that sentence back to the digits from the table, you get the following:
My turtle Pancho will, my love, pick up my new mover, Ginger. 3 1415 926 5 3 58 97 9 3 2 384 6264
Lets go a bit further. Add these sentences to the previous one and you've got the first sixty digits.
My movie monkey plays in a favorite bucket. 3 38 327 950 2 8841 971 Ship my puppy Michael to Sullivan’s backrubber. 69 3 99 375 1 05820 97494
Finally, lets crank it up to a hundred digits.
A really open music video cheers Jenny F. Jones. 45 92 307 81 640 62 8 620 Have a baby fish knife so Marvin will marinate the goosechick. 8 99 86 28 0 3482 5 3421 1 7067
Here are all the sentences written together:
My turtle Pancho will, my love, pick up my new mover, Ginger. My movie monkey plays in a favorite bucket. Ship my puppy Michael to Sullivan’s backrubber. A really open music video cheers Jenny F. Jones. Have a baby fish knife so Marvin will marinate the goosechick.
By the way, I learned this trick from Prof. Arthur Benjamin's excellent book Secrets of Mental Math. This book is full of mental math techniques and I highly recommend it. Here are some other links of interest: