ab * ac where ab & ac are two-digit numbers, and b+c=10.
In reality, (10a+b)(10a+c) = 100a^2+10ac+10ab+bc
Some reverse distributing, 10a(10a+c+b)+bc
Since b+c=10 and b+c=c+b, then 10a(10a+c+b)+bc = 10a(10a+10)+bc = 100a(a+1)+bc.
This trick is only a corollary of that general rule the gentleman instructed upon.
it works for any … it works for any double digit numbers, with the 1st digits being the same and the 2nd digits summing up to 10.
ie. 43×47, just multiply 1st digit by next higher (in this case 5, so 4×5=20), and write the product of the last 2 digits (in this case 3×7=21)
and there you have it,
43×47=2021
How to square a number that ends in 5. Without a calculator.
That will come in …
That will come in very useful in my Physics class.
yea..if u read the …
yea..if u read the info and listened he said that it’s only for numbers that end in 5
but the square of …
but the square of 12 is 144 while in ur way is 24 is that onnly if the last number is 5??? nice try!!”=)
nice vid, the sound …
nice vid, the sound quality wasn’t the greatest though
does 777 edd with 5?
does 777 edd with 5?
ok i take that back …
ok i take that back..777×777 dosent work…..why dont you get high off that dry erase marker you virgin for life
wow thats awsome
wow thats awsome
Hey, thanks! I’d …
Hey, thanks! I’d never seen it proven before.
Proof for this …
Proof for this trick…
ab * ac where ab & ac are two-digit numbers, and b+c=10.
In reality, (10a+b)(10a+c) = 100a^2+10ac+10ab+bc
Some reverse distributing, 10a(10a+c+b)+bc
Since b+c=10 and b+c=c+b, then 10a(10a+c+b)+bc = 10a(10a+10)+bc = 100a(a+1)+bc.
This trick is only a corollary of that general rule the gentleman instructed upon.
it is only with the …
it is only with the 5 at the end? i tried 72*72
it works for any …
it works for any double digit numbers, with the 1st digits being the same and the 2nd digits summing up to 10.
ie. 43×47, just multiply 1st digit by next higher (in this case 5, so 4×5=20), and write the product of the last 2 digits (in this case 3×7=21)
and there you have it,
43×47=2021
hmmm… not very …
hmmm… not very interesting… much better the hot chicks from <b>LikeHerAss.com_<b>
see how a hot chick …
see how a hot chick loses a bet and has to strip in front of her classmates <b>(_stripAss.com_)<b>
I see I’m not the …
I see I’m not the only one who thinks so. Wish I could write with cool flourishes like that.
Oh, nice math trick, too.
)
well, does 777 end …
well, does 777 end in 5?
Awesome!!!
Awesome!!!
fuck off u twat, i …
off u twat, i knew this years ago
it indian vedic math, stop stealing our stuff u honkey
Try 777×777 it does …
Try 777×777 it does not work guys!
Ummm this only …
Ummm this only works with the last digit being 5
im going to tell my …
im going to tell my math mate about that, he’ll love it
nice. i’ll use that …
nice. i’ll use that for the number sense test
Wo….your hand …
Wo….your hand writing is amazing!
Wow… Cool..I love …
Wow… Cool..I love math tricks.. Hey, I like your handwriting style. Mine is like chicken scratches!
That was a good one.
That was a good one.
Nice, Have you ever …
Nice, Have you ever heard of the rule of 72? That one can make you wealthy.