Memorising and recalling pi

#1

Hi,

Having been slack for several months, I’m now getting back to memory work. One feat I’d like to master is memorising/recalling pi.

I’ve begun easily enough with the first hundred digits and, having only got started this afternoon, have been able to hit scores of 10/10 when asked where random numbers occur. (I should increase this number, but it seemed enough to start off with.)

I wondered what methods people use to pinpoint exact locations - eg the 19th/54th/92nd etc number of pi. For the first hundred, I memorised the first 100 in batches of 3 digits, then simply recalled where the 30/60/75/90 cut-offs were. That - and simple maths - allowed me to know where random numbers fell.

That’s fine for just 100 digits but probably unworkable if I go much higher - which I’d like to.

Thanks,

James

(Josh Cohen) #2

If you use a memory palace, and you always using the same number of digits per location, you can calculate the position of any digit. If you have three digits per location, and someone asks you for the 95th digit, you can divide by three to find the location (31 – may need adjustment depending on how you are calculating the number of digits) and then move a few digits past that to get to the 95th digit.

To keep track of the positions, you can mark every 10 locations with a number shape image. I have the first 400 digits memorized in rows of 10 with 4 digits per location. So the first row is marked with a candle (1), the second row is marked with a swan (2), the third with a butterfly (3), etc.

If that explanation doesn’t make sense, I could write it out in more detail.

There’s also a guess pi digits game that you can use to practice.

#3

Thanks for the tip Josh. I was just looking for something like this for another problem. Numbers are given in 25 rows of 40 digits and I wanted a check build in. Sometimes I forget a number during recall or I skip a locus during memorization. This can be a costly mistake because than every row under the mistake would be zero points because every number is a position ahead or back. So this is very helpful for me. Thanks a lot!

#4

Many thanks, Josh. I’ll try out that approach. It certainly seems to make a lot of sense.

(Josh Cohen) #5

If you have 25 rows, another idea would be to use an alphabet peg list to mark the rows, because there are just enough letters for that task.

A = alligator – marks row 1
B = bear – marks row 2
C = cow – marks row 3
etc.