No, I’m not going to link to it. That’s what they want.

The video purports to show a trick for working out roots. For example, it calculates $\sqrt[2]{25} = 5$. So far, so un objectionable. However, the method? They add 2 and 5 (the digits of 25), then subtract 2 (the number on the “tick”).

They do the same for $\sqrt[2]{64}$. And for $\sqrt[2]{196}$. Also $\sqrt[3]{3375}$, which is 15.

Why is this awful? It works, doesn’t it?

NO, IT DOESN’T. THAT’S NOT HOW THIS WORKS. THAT’S NOT HOW ANY OF THIS WORKS.

It “works” for those cherry-picked examples. But if you try it for other numbers, you find that $\sqrt[2]{16}=5$ as we ll. Come on, now, it must be one or the other! $\sqrt[2]{49} = 11$, which is more than $\sqrt[2]{64}$. Huh! Weird, eh? And as for $\sqrt[2]{100}$ being -1, well now, it looks like we’ve discovered an entirely new branch of maths.

I genuinely don’t understand why you’d make a video like this (other than, perhaps, to create rage-bait and/or test people’s critical thinking skills). If you’re doing it from a position of ignorance, you have a responsibility to check the things you’re saying make sense. Worse, if you’re doing it from a position of knowledge, you’re actively misleadin g people and you should be ashamed of yourself. Go dig a hole.

You could, possibly, do an ethically defensible piece on this nonsense, but only by saying “this numerical coincidence only works fora few specific cases. Can you find them?” That – I’d be ok with that.

In the meantime, I’m going to find the perpetrators of this outrage and bring them to justice.