Mathematical Amusement

Many brainers might have played with the math game “combine 24”.

  • 1,3,3,9 = 24 ? → (1+3)*(9-3) = 24
  • 2,5,4,7 = 24 ? → ((5 + 7) / 2) * 4 = 24
  • 3,7,9,18 = 24 ? → * (3 * (9 - 7)) + 18

It is a good game to challenge your math sense…
Wait! Wait! If you are not interested in solving Math type of questions, I still beg your attention. Since this is a fun chat, I hope that you can treat my following words as a simple art piece. This could be beyond your imagination, right now I wish you can set your mind free and have a wonderful journey with me.

Precedents are embarked in our minds, we love 1,2,3,4,5,6,7,8,9 …
And if some points are presented this way,
3. item c
7. item b
2. item a
we would opine that it is messy. And this brings us to the main dish of today!


Ugh, cool… But how is it related to the Art of Memory?

I will describe 2 ways of using this math amusement.

  1. Memory training of operands and operators
    Instead of training numbers discipline every day, I guess people are more interested in memorizing some fun facts. When you present to your audience thousands of Pi or only a hundred of Euler numbers, I would say most listeners lose attention after listening >20 numbers. Also, they might consider you as a math greek,
  • Oh, this man is genius, he can memorize many digits of Pi. Umm, can I leave now? Those numbers are lengthy and mean nothing to me… :woozy_face:
  • [Alternative] “Tell me a number between 1-100, I can show you my black magic, translating the numbers into the order of 1,2,3,4,5,6,7,8,9!”
  • NO WAY! how can you do that??? How about 37, 82, 99?
    With this fun fact, you can have more interaction with your friends.
    Disclaimer: To math experts, this is a smirking trick.
  1. STEP RECORDER (prototype)
    This is a potential upgrade to memorize steps and locations simultaneously.
  • remembering a row of the chessboard: 45 = 1+2+…+8+9; all + means pawn :chess_pawn: , and indicates the beginning of a game, row 2/7. You can apply this concept for each row, and get 8 numbers to represent a broad.

    "You must be kidding? How come I can use the above table to represent a row of immense situations.
  • Believe it or not, you can also do the math for 101, 102, 103, … , 10k!!! :crazy_face:
  • In sports, say parkour, you can use the table to represent a consecutive action with a clear footstep.
    So as in musical instruments, say flute the fingers positioning.
    Disclaimer: To remind you, this is an imaginative use of the table, the practical implementation, I will leave it to your intuition.

Hoo… :relieved: Thanks for your precious time, I hope you had an interesting journey with this episode. Off the topic, I considered an end for me from a frontline active poster to a silent audience. This means I will keep quiet in this forum but still, I will keep reading all the great brainers’ work. Finally, I sincerely hope that everyone in Art of Memory can find their path to a bright future.

Yours faithfully,


This is fun, to my mind camed question, what is smallest number that can’t be written as resault of operation you suggested?

(Can we find such number for any other base without trial/error method)

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It can be solved, but the answer varies.
The main determinant is about what kind of operator is eligible. Once, you defined it, the only way is to trail an error by computer, until the number can’t be formed.

For now, u can simply treat 10k+2 is the number can’t be written down, with all the operators you had seen in my sheet.

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Thanks for sharing :slightly_smiling_face:

We would be very happy if you could give us some examples in chess or musical instruments using your methods.

Wish you good luck!