The magic pyramid of numbers

I was blown away when I came across the magic pyramid. I don’t know who discovered it, but here it is –

I simply had to sit and figure out why it worked, and it turned out to rely on the fact that 9 times any of the numbers on the left is almost exactly a string of ones.

Typically, 9 x 123456 = 1111104. If you add 6 (the last digit in 123456), then it does come to a string of ones followed by a 0, that is 1111110

And if you subtract 123456 from that (to get times 8 instead of times 9) you get 1111110 – 123456 = 987654.

Phew! It’s one thing to figure out why it works, but whoever discovered it out in the first place must be somebody with a very special brain.


    1. It’s been fine for a long time. We still have to wear masks outside and sanitise when entering a shop, but that’s about it.

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