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Comment by mkirsten | Hacker News Reader

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mkirsten·

Can you try calculating 101 * 70 in your head?

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I think therefore I am calculator?

Very easy to solve, just like it is easy to solve many other ones once you know the tricks.

I recommend this book: https://www.amazon.com/Secrets-Mental-Math-Mathemagicians-Ca...

Completely missing the point on purpose?

Elaborate.

you don’t solve it by brute forcing possible solutions until one sticks

Yeah, read it in another comment. Why do you think doing calculations in your head is brute-forcing? Many people can do it flawlessly, without even knowing of these "tricks". They just know. Is that brute-force?

I can absolutely try this. Doesn't mean i'll solve it. If i solve it there's no guarantee i'll be correct. Math gets way harder when i don't have a legitimate need to do it. This falls in the "no legit need" so my mind went right to "100 * 70, good enough."

Or you could do (100 + 1)*70 => 100*70 + 1*70

Um, that's really easy to do in your head, there's no carrying or anything? 7,070

7 * 101 = 707 * 10 = 7,070

And computers don't brute-force multiplication either, so I'm not sure how this is relevant to the comment above?

I think it is very relevant, because no brute-forcing is involved in this solution.

That's not true, the 'brute force' part is searching for a shortcut that works.

The brute force got reduced down to fast heuristics, like Arthur Benjamin's Mathemagics.

It’s almost like you’re proving the point of his reply…

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