Can anyone give me a quick explanation for this ?
The number is always going to be divisible by 9.
When you follow the procedure, you always get a number that’s a multiple of 9. On the table of symbols, each of the possible multiples of 9 will have the same symbol as all the others.
No, I mean why do they have a gopher in a turban? What’s that supposed to mean?
I guess it’s supposed to be one of those fortune-telling gypsy gophers.
You mean the ones my mother warned me aboot?
Hey, if you’re lucky enough to find an animated gopher who can read minds, you let him wear whatever the hell he wants.
How do we know it’s a “he”?
And he’s got a mini-me!
Here’s a fun fact that I just learned and is kinda relevant here. If you’re balancing your checkbook and you come up with a number that is not what the bank says you should have, subtract the two. If the difference between the two numbers is divisible by 9, you’ve likely transposed something when writing it down - writing $9.82 instead of $9.28.
Kinda the same deal.
I can balance my checkbook on my nose.
This puzzle is a variation on the theme.
Here’s how it works algebraically:
Let the first digit be a and the second digit be b.
For example, if you choose the number 83, then a = 8 and b = 3.
-
Select a two digit number
83 = 10a + b -
Add the two digits together
11 = a + b -
Subtract the sum in step 2 from your original number
72 = 10a + b - (a + b)
= 10a + b - a - b
= 10a - a + b - b
= 9a
Since 9 times anything is divisible by 9, then your final result in step 3 will always be divisible by 9. This proof can be used to prove the divisibility rule for 9 and (with a slight twist) for 3 as well.