so then, you probubly think that i don't live up to my name-that i am
an idiot, not an genius. well then, here is a kind of proof-i will find a
better one soon. but anyway-please pick a 3-digit number where all
three digits are different, i.e. 123, but not 121. right, then reverse it
to make 321, or whatever. now, take away the smallest number from
the largest (321-123=198). now reverse that answer(198 to 891). now
add that number to the answer of the subtreaction (198+891). what is
the answer?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
1089, of course. now then, the tricky bit. why. can anybody give me a
sound algebraic proof as to why this, erm, phenomina, happens-
WITHOUT doing a search on the internet, or asking your dad/maths
teacher/professor/friend/etc. anyone? i will produce mine in about a
week.
oh-by the way-if you end up with 198, just carry on from there, and
you will get 1089.
let me try.
lets call the number ABC. Lets Assume A>C (otherwise we reverse the
number to start with).
so the algebraic value = 100A + 10B +C
the reverse = 100C + 10B +A.
We substract: 100A+10B+c - 100C-10B-A = 99 (A-C)
that means a 99-fold.
all 99 folds (the first 9 only are relevant) have one 2 things in
common: middle cypher=9, the sum of left and right cypher = 9.
the sum will therefor allways be :
least significant digit= 9
middle digit= 8 (9+9=18)
most significa, digit(s)= 9+ 1 carry over from the middle= 10
result = 1089
about right?
sin.
No that is not right.
What you should do is tell people you have a brilliant memory.To
prove it you say:You have memorised the phone book,then you use
your trick to find a"random" number,you get them to agree that that
was a random numder,then you tell them to go to page 108,and
thumd down to 9-that's the only one you need to memorise.
Lyn.