Math Anxiety
Posted by protozach on December 24, 2009
UPDATE: Okay, fine, base-14.
Bonus points if you can solve for (math anxiety face) tetrate (math anxiety face).
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Miro said
what the?! Aren’t there supposed to be only 13 symbols for a base 13? I look exactly like the math anxiety face now…
Miro said
And why does the second number start with 0…
However, I would guess 3668796254007 in base 10, it would take some time to draw the base 13 answer
Sanjay said
Should there be a symbol for 13 in base 13?
Demosa said
Think about it, Binary (base 2) has two symbols, typically 0 and 1, base 10 has 0-9. There shouldn’t be a symbol for 13 in base 13, but the problem can still be solved, treating it as 13 base 13.
left side (base 10 equivalent symbols)
1 7 2 5 2 11 1
A = [0 2 8 6 4 13 12]
B = [0 10 0 5 1 11 12]
A.*B = [ 0 20 0 30 4 143 144]
Reducing and carrying
[1 7 2 5 2 11 1]
Still the only Geek Gurl here it seems! (Richa) said
but err…isnt it base 14 in the problem?
Sanjay said
I guess that answers my question.
Moe said
That’s base-14 though? There’s no symbol for the number a math is the base of. (there’s no symbol for 10 in base-10 or 2 in binary.)
So assuming base-14, [3*14^5 + 8*14^4+ 6*14^3 + 4*14^2 + 13*14+12] * [10*14^5+5*14^3+1*14^2+11*14+12] = 1.0451625 × 10^13
Moe said
whoops, [2*14^5 + 8*14^4+ 6*14^3 + 4*14^2 + 13*14+12] * [10*14^5+5*14^3+1*14^2+11*14+12] = 7.55150479 × 1012
protozach said
You have to write the answer in base-13 or you lose!
T3h Ub3r K1tten said
Maybe I’m just simple, but I think the extra value for 13 is the joke.
Ickis said
THERE ARE NO JOKES IN THE MATHROOM!!!
John said
Seconded.
r said
Oh, I get it. ROT-13. very clever.
jolson42 said
Ok, Moe got the base 10 answer (7,551,504,790,596), but so far nobody has given the base 14 answer.
In traditional base 14 notation, it’s 1C1,6CD,979,044. I’m not sure how to type that in math-anxiety-face notation, so I MS Painted it. Follow the link in my name to see it.
I also included an answer for the bonus question, but obviously it isn’t written out in full.
LN said
Am I the only one who didn’t convert to base-10? Well, it might make it more difficult, I suppose. In traditional base 14, though, I have 1C1,6AC,D79,044.
I’ll work on the base-13 version later.
Tori said
I’ve got the same thing for base 14. As for base 13 (traditional 13, not the anxiety faces), it should be 42A,147,1C4,A50.
whatisfgh said
hmm.. did he ninja edit this? I swear it was base 13 the first time I read it.
Lex said
UPDATE: Okay, fine, base-14.
Yeah, he did ninja edit it. Personally, i liked the ROT-13 idea.
r said
I know, right? hey, let’s make a self-encoding variable bases system and solve the problem that way!
Blue said
Just prior to the “ninja edit” that re-cast the problem as base-fourteen, I was going to about to submit these comments:
Post-edit, we find that the “thirteen” digit doesn’t hint at hidden cleverness, but at a typo in the problem description. So, maybe this is an arbitrary-and-unnecessarily-complicated arithmetical chore after all. :/
notevenwrong said
Where did all of this discussion about base 13 come from? The question clearly states that it’s all in base 14, and every symbol necessary is provided. Also, wouldn’t it be easiest to do it by hand like in elementary school?
PhilosophicalHamster said
As stated above, the problem was accidentally posted referring to “Base 13,” probably to make a ROT-13 joke, but there was a ninja edit to fix to Base 14 when people started pointing out that there is no numeral for 13 in Base 13, just as there is no numeral for 10 in Base 10. (The standard symbols for bases higher than ten is to start using capital letters after 9. This problem is just to screw with visual learners.)
PrarieDog said
ok, I worked it out in base-14, and I think the answer is 1,12,1,6,12,13,9,7,9,0,4,4
I’m sure there’s a better notation, but it’s just comma delimited so you know where the digits start/stop.
I also wrote it down in Zach’s symbols, but I think that would be impossible to type…
rom_maniac said
It is, however, quite possible to present in image form.
http://i48.tinypic.com/f05c3o.png
I did work it out in base-14 by myself, by the way.
rom_maniac said
Oh, I see that someone had already given the answer in image form. My bad.
LN said
At least I’m not alone in my self-inflicted punishment. Looks good.
karatechop said
I have math anxiety. I hate your forever. Im going to go quietly whimper in the corner now. Your on my LIST!
Mazen Mokhtar said
I got (2864DC base 14) x (0A051BC base 14) = 1400418 x 5392322 = 7551504790596 = (1C16CD979044 base 14)
Calvin said
Having just arrived at this site, mentally doing the majority of the problems (Not the Santa one. My mind is limited to 10 2-dimensional complex numbers at a time when dealing with fractions.), my mind is still playing “Jingle Bells” on pseudo-infinite loop. This brought to mind the following query: Good list or bad list? XD
eman said
Oh, and (math anxiety face) tetrate (math anxiety face) = 13 tetrate 13, which is a power tower of 13 13s:
13^13^13^13^13^13^13^13^13^13^13^13^13
You can only evaluate the uppermost exponent:
13^13^13^13^13^13^13^13^13^13^13^302875106592253
You can’t write down the next exponent, 13^302875106592253, because it has about 337 trillion digits. And 13^13^302875106592253 is larger than a googolplex and has many more digits than there are particles in the universe.
Anyway, in base 14, D tetrate D is
D^D^D^D^D^D^D^D^D^D^D^54B133A5506CD
eman said
Here’s the answer in Zach’s silly notation.
http://i48.tinypic.com/t05j7p.jpg
Sam Morriss said
Seems somehow … familiar …
http://myst5.com/dninumbers.html
btfx said
http://www.wolframalpha.com/input/?i=%283*14^5+%2B+8*14^4%2B+6*14^3+%2B+4*14^2+%2B+13*14+%2B+12%29+*+%2810*14^5+%2B+5*14^3+%2B+1*14^2+%2B+11*14+%2B+12%29
Eric said
Really just posting to ask for more of these. Rather enjoyed this site.
But since I feel obliged to make a related comment under something while I’m posting so it’s at least partially on topic:
As obviously realized by some but not by others there’s nothing magical about base-10. The techniques you learned in elementary school still work. Even many of the tricks work but many need minor adjustments, like to see if a number in this base is divisible by d in base-14 (instead of 9 for base-10) I can add up the digits and see if that sum is divisible by d. So many people put this into a computer and converted to base-10 then back, but, the problem is clearly intended to be worked out in base-14 so your work should have looked something like this:
2864dc
x a051bc
——
23363c4
208dcc6
2864dc
d03ad4
+1c077c8
————
1c16cd979044
I used 0,1,2,3,4,5,6,7,8,9,a,b,c,d instead of the other symbols.
With a whole bunch of little numbers written down and likely erased to carry digits.