Unlocking the 'Infinite Memory' Math Trick: How Does It Work?

Hi everyone! Here I want to describe a fascinating math trick that makes it seem like we have infinite memory!

The trick involves creating a set of cards labeled from 1 to 50 (or any other number), with each card having a seemingly “random” 8-digit number written on it. When someone picks a card and shares the label, we can instantly recall the 8-digit number—making it appear as though we have limitless memory!

Here's the secret: rather than memorizing all the numbers, we employ a smart encoding method that enables us to mentally generate the 8-digit number instantly! The concept involves using a straightforward mathematical rule to create a number that appears random but is simple to calculate in your head (I'll be uploading an intriguing blog post on the history of encoding soon!).

How it Works

Let’s walk through an example to demonstrate the trick. Say the chosen number is 23. We use the following steps to generate an 8-digit number:

1. Multiply the chosen number by 4.

   For 23, this gives:

   23 × 4 = 92

2. Reverse the digits.

   Reversing 92 gives:

   29

3. Continue generating digits by summing the previous one or two digits, ignoring any tens (i.e., just use the last digit of the sum).

   So, starting from 29:

   • Next digit: 2 + 9 = 11 → write down the 1 (ignore the tens).

   • Next digit: 9 + 1 = 10 → write down the 0.

   • Next digit: 1 + 0 = 1 → write down the 1.

   • Next digit: 0 + 1 = 1 → write down the 1.

   • Next digit: 1 + 1 = 2 → write down the 2.

4. Keep going until you have 8 digits.

   For 23, the final 8-digit number is:

   29101112

Now, when someone picks card 23 and asks for the 8-digit number, we can simply do this quick calculation in our head and confidently respond with 29101112—making it seem like we have memorized the number all along!

Example with a Different Number

Let’s try another example, say the number is 17:

1. Multiply by 4:

   17 × 4 = 68

2. Reverse the digits:

   68 becomes 86.

3. Continue generating digits:

   • 8 + 6 = 14 → write 4.

   • 6 + 4 = 10 → write 0.

   • 4 + 0 = 4 → write 4.

   • 0 + 4 = 4 → write 4.

   • 4 + 4 = 8 → write 8.

4. Final 8-digit number for 17:

   86440448

This simple method allows us to generate what looks like a random number, but it’s really just the result of a straightforward mental calculation. The trick is impressive because it appears as though we’ve memorized all these random 8-digit numbers, when in reality, we’re just computing them on the fly!

With practice, this trick becomes quick and effortless, and you can amaze your friends and family by appearing to have “infinite memory.”

Share your thoughts in the comments below!