Your fingers are secretly a powerful calculator

What sorcery is this?! You can easily multiply numbers from 6 to 10 just by counting your fingers. #math #maths #mathematics #shorts

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[ZzSlumberzZ]

when you have to multiply 1828×9273 and the teacher starts throwing gang signs

[connorstarnes]

imagine a professor is teaching a calculus class and pulls out his fingers to multiply

[saikitonia]

this seems like it would be harder to do than just multiplying normally

[dimpufrn]

For any integer a and b where 6 ≤ a, b ≤ 10, then

The "touching fingers and the ones below" part translates to

(a - 5) + (b - 5)

which then multiplied by 10 because it's placed in tens place, becoming

10 × ((a - 5) + (b - 5)) ... (i)

The "above touching fingers" part translates to

(10 - a) × (10 - b) ... (ii)

Adding (i) and (ii) together we get

10 × ((a - 5) + (b - 5)) + (10 - a) × (10 - b)
= 10 × (a + b - 10) + 100 - 10b - 10a + ab
= 10a + 10b - 100 + 100 - 10b - 10a + ab
= (10a - 10a) + (10b - 10b) + (100 - 100) + ab
= ab

which is the product of a and b

–––
Just my view on this

[dreed]

It's incredible that anyone would choose this rather than memorizing their multiplication tables.

[hunter_greene]

Who made it through school without having to memorize every single digit multiplication table?

[Durkheimm]

this is very interesting!
it may not be practical, but I think it can evoke curiosity and love for math, especially in children
could you do a video on why it works?

[justacatinprofile]

Me who can finally multiply without using my brain power: thank u

[aguyontheinternet]

What sorcery is this?! But seriously what is this, why does it work?

[konoveldorada]

When you don't have fingers remaining to add:

[drenz]

'We touch the fingers of 6 and 9"
Don't say it don’t say it don’t say it I CANT CONTROL IT-

Noice.

[Yusso]

Instead of doing this bs I'll just memorize the 15 results.
6x6, 6x7, 6x8, 6x9, 6x10, 7x7, 7x8, 7x9, 7x10, 8x8, 8x9, 8x10, 9x9, 9x10, 10x10
That's all.

[unbearifiedbear]

Instructions unclear; got shot in Compton

[maxgluteus]

Multiplication table is evil, made me miss so much

[karkador]

this is way harder than just remembering

[AlwaysOnForever]

I would rather memorize the multiplication from 1 to 10 over this 1000%. I already memorize to the point its a reflex and doing this is hell

[mustafashaban]

As my father once said "learn your damn multiplication tables, boy!" right before he beat my ass

[mathprodigygamer]

Instructions unclear, can’t multiply any two numbers less than 6

[martynas]

We touch the “fingers” of six and nine
Kid named six: 😳
Kid name nine: 😏

[studstud]

I tried doing 6 times 6. And realised that I have one finger less than everyone else! Because I could only count two touching fingers and no fingers below. But I needed a 3 🤯!