The number 9

I gave this a shot using 54 5 (+) 4 (9) 9 ———— 4 6 = 10 Not 9 (nine) If I hit this anomaly on first try, there are likely others which eliminates his “Rule”

😬

In any base X system, this will get you X-1. Honestly not that interesting, trivially true, and probably not applicable to anything.

It's a fucking trick for base ten math. It's not rocket science. Stop doing math tricks or you'll end up as stupid as this idiot!🤨

Let first digit be a, second digit b. The general formula is 10*a+b - (a+b). It always gives you 9a. For 10-19 it’ll be 9. For 20-29 it’ll be 18 etc.

When I was in high school, I noticed that if you subtract any 2-digit number from its reverse, the answer is always the multiple of 9 times the difference between the two numbers: 84-48=36; 8-4=4; 9x4=36 72-27=45; 7-2=5; 9x5=45 31-13=18; 3-1=2; 9x2=18 52-25=27; 5-2=3; 9x3=27

It works because there are only ten total numbers The number 0 carries no weight so you stop at 9 and start over with 1

Youre just subtracting 1 from 10 each time, the second number is just cancelled out

Schoolhouse Rock pointed this out decades ago w/ multiplication. The 2 digits always add up to 9. “You could multiply your # by 10 and subtract that number from the product and you get the same result.” Is a wild line to spit at a 3rd grader, but they’re wonderful videos.

638 -17 —— 621 =9 Wow-Mind blown

I went in did my age and got 9. Then I looked at the time and screamed 🤣🤣🤣

The kinda shit 8 year old me was finding out. Are people amazed by this shit?

This is unironically 100% proof of an intelligent designer / creator.

I mean it works but what’s the application?

Ok but like, what do I do with this information

This is how I learned about the greatness of the number 9.

"Number 9...number 9...number 9..." - Ringo Starr, 'Revolution #9' - the Beatles.

9 is the largest number. There is no number larger than after 9, you start over

Dang he didn’t show hundreds? Thousands? 142 = 1+4+2= 7 142 -7 —— 135 = 1+3+5= 9 dang.. ————————— 248,322 = 2+4+8+3+2+2=21 248,322 -21 ———— 248,301 2+4+8+3+0+1=18 1+8 = 9 Danggg

I got stuck on this one for a while it used to keep me awake at night. Best conclusion I came up with is mathematically everything is a sphere expanding and 9 is the center point or geometrically it would be a 90 degree angle from the center point and you are going straight in one direction off of 9 . Hope that makes sense.

Here’s the explanation for why this is true. Also every 2 digit multiple of 9 except 99 adds to 9. That’s why this phenomenon is happening. Very cool!

This works in base 10. In octal, the number 7 would be magic. I taught my wife a trick, and she taught it to all her tellers: Take any number. Transpose its digits all you want. Then take the difference between the new number and the original. It will always result in a multiple of nine. When a teller is out of balance, first check the amount of the out-of-balance. If it is a multiple of nine, look specifically for an error in a transaction caused by a transposition of digits.

Wow. This clown is an expert at amusing himself. Not sure this needs to be shared with the rest of us.

Ok great. And now of what use is this? Or is it just something to do for fun and show other people?

I’ve been doing this in my head my whole life have no clue why…

Me when it’s time to break out this party trick:

61 6+1=7 61-7=54 5+4=9 🤯

Let a 2 digit number be represented as 10x + y, where x and y are the digits of the number. Sum of digits, s = x+y Difference of the number with digit sum = 10x+y - (x+y) = 9x. Hence the diff will always be divisible by 9.

It's called base 10. No magic about that 😬

@freeland_spirit Ok. Check out this one.😆

5648 5+6+4+8 =23 5648-23=5,625 5+6+2+5 =18 1+8 =9 What insanely fun trick

@grok give me a breakdown on the mathematics here what’s he doing? What is this called? Thank you in advance.

This Gen X man gone lose his mind when he finds out about numberology. 😂

It's so interesting Nikola Tesla always was intrigued with the nine 369 but especially nine

It’s an artifact of Base10. If you play around with other bases you discover the specialness of the last single digit in those base systems. Like, in hexadecimal it’s 0xF that becomes special. 0x2E -> 2+E= 10. 2E-10= 1E. 1+E = F!!! See?