• We’re currently investigating an issue related to the forum theme and styling that is impacting page layout and visual formatting. The problem has been identified, and we are actively working on a resolution. There is no impact to user data or functionality, this is strictly a front-end display issue. We’ll post an update once the fix has been deployed. Thanks for your patience while we get this sorted.

Brain Teasers

C

Chelsey

Senior member
First person that gets these correct gets a :cookie:

First one:
Totally odd
When we multiply multidigit numbers, we have to do some addition as well - the final step is to sum the subtotals. Here's a puzzle that exposes the steps and tags the various digits as odd ("O") or even ("E"):

EEO
X OO
---------
EOEO
+ EEO
----------
OOOOO

Find the numbers that satisfy this scheme.

The algebra of cooperation
Solve the number rebus
USA+USSR = PEACE
The same letters stand for the same digits, different letters denote different digits.

Restore the Product
The figure shows a product in which some of the figures are rubbed out and replaced by asterisks. Restore the absent figures.

*1*
X 3*2
--------
*3*
3*2*
*2*5
--------
****3*

Mirror Numbers
Two numbers are called mirror numbers if one is obtained from the other by reversing the order of digits--for example, 123 and 321. Find two mirror numbers whose product is 92,565.

There are a few more, if I can figure out how to make the graphics then I will post them as well. Thanks in advance for your answers!
 
u: 4 s: 8 a: 3 e: 5 c: 6 r: 2 p: 0 483+4882=05365
u: 8 s: 6 a: 5 e: 9 c: 2 r: 4 p: 0 865+8664=09529
u: 8 s: 7 a: 6 e: 9 c: 4 r: 3 p: 0 876+8773=09649
u: 9 s: 3 a: 2 e: 0 c: 7 r: 8 p: 1 932+9338=10270

I'm just too slow for chuckywang here....
 
Originally posted by: chuckywang
Originally posted by: Kyteland
287*39=11193

681*17=11577

861*13=11193
Click to expand...

Nice, i was just about to post 861*13
Click to expand...

That's the great thing about a brute force c++ program. It checks everything. I had to revise my answer twice because of a bug though.

You must have had a 5 min head start on the other problems. You kept getting them faster than me.

Yeah, that's the ticket, a head start. :shiftyeyes;
 
Originally posted by: Chelsey
Ok guys, I've only got one left, and that's the Totally odd one. Someone's gotta be able to figure it out!
Click to expand...

How can an odd + odd = odd? (in the ones digit of the summation) There's something wrong with your formatting or the original problem.

EOEO
XEEO (x is a spacer)

EOEO
EEO

Both scenarios cannot equal OOOOO. The first you cannot get an odd+odd = odd in the ones digit.

The second is that in order to get E+E = OO in the thousands digit, you need a carry of 1 from the addition of O+E in the hundreds digit. If O+E carries a 1, the O+E from the tens digit will carry a 1 and then the hundreds digit cannot be O.
 
before you get to the odd + odd = odd in the even odd problem,

note that the algorithm being used isn't one where you use 0 as a placeholder...
the +EEO on the 4th line is shifted over by the + sign.

(otherwise, how can you multiply the original 3 digit number by a certain number of 10's and get a number less than 1000?)

It should read
EOEO
+EEO0

look carefully, there's a zero there. (Using the most common algorithm used for grade school multiplication in the U.S.)
 
I gave it a quick shot... I'm not writing any code to figure it out, or trying any harder

close but no cigar:
881
*17
-------
6167
881
--------
14977

That should at least give the idea... the 4 ruins it, but that's what the problem means.
 
Bump

This is due soon guys 😛 I think it's the way my teacher wrote it, you're probably right about the zero. So, let's assume that it's what Dr. Pizza said, EOEO
+EEO0
 
Originally posted by: Bound_Vortex
681
*17
-------
4767
681
--------
11577
Click to expand...

how bout that... my intuition was pretty close... I had thought about it for 30 seconds... attempted 881*17 and quit.
 
You must log in or register to reply here.

TRENDING THREADS

Back
Top