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Re: Paper/Pencil Problems

Posted: Tue Aug 30, 2011 8:44 pm
by idantlol
Well, it would be a little dishonest to say yes, since the variety of methods I've been using to answer those type of question have typically been dubious (although I made the effort to solve 138 'legitimately' with a bit of basic algebraic number theory). But I cannot see why the general strategy should fail for some equations and not others, and the forums for the problems I suggested have answers from people who actually did them properly properly rather than just found something that worked or checked *that* website which solves such things for you.

Re: Paper/Pencil Problems

Posted: Thu Oct 06, 2011 11:49 am
by Francky
PE197, first time by dBlade 10 Jun 2008 10:45 am.

Re: Paper/Pencil Problems

Posted: Thu Oct 06, 2011 12:02 pm
by hk
Francky wrote:PE197, first time by dBlade 10 Jun 2008 10:45 am.
That's no pencil and paper but calculator and thumb. (pun intended).

Re: Paper/Pencil Problems

Posted: Thu Oct 06, 2011 12:22 pm
by Francky
hk wrote:
Francky wrote:PE197, first time by dBlade 10 Jun 2008 10:45 am.
That's no pencil and paper but calculator and thumb. (pun intended).
I would say, it's possible to write a proof with pencil/paper, and finish with calculator, as mentionned in the first post of this thread.
But it's true, it's not a single expression, we have to do more than press enter.
So, I don't know, now.

You know that I don't like (I hate) solutions where people choose bounds* or methods* for their convenience, or other kind of cheat ...
* unless it's prooved.

Here, I just would say, that's "possible". (?)

Re: Paper/Pencil Problems

Posted: Sun Oct 09, 2011 12:11 pm
by juanchodepisa
I'm pretty sure someone willing to perform some tedious arithmetic operations, can solve Problem 94 (View Problem). It can definitely be solved by calculator. I would have, but couldn't be bothered (rather coded some Python :-P )

Re: Paper/Pencil Problems

Posted: Wed Oct 12, 2011 4:54 pm
by Rainy Monday
I'd say Problem 33 (View Problem) is a fine example too.

Re: Paper/Pencil Problems

Posted: Fri Oct 28, 2011 3:19 pm
by Fogmeister
I'm almost certain that Problem 44 is possible with pen and paper.

I just haven't quite worked out exactly how yet :D

Will update when/if I get there.

Re: Paper/Pencil Problems

Posted: Sun Dec 11, 2011 1:49 am
by PurpleBlu3s
I nearly tried 107 by hand. If I can be bothered I may still try, because I don't think it would take that long using the algorithm I coded to solve it. It would be similar to doing 96 (Su Doku problem) by hand although far less work, but still fairly tedious.

Re: Paper/Pencil Problems

Posted: Wed Jan 11, 2012 8:08 am
by Eternalcode
You can also solve 205 with a pencil and paper.

Re: Paper/Pencil Problems

Posted: Wed Jan 11, 2012 1:53 pm
by Marcus_Andrews
335 and 345 are doable

Re: Paper/Pencil Problems

Posted: Tue Jan 24, 2012 7:59 am
by Eternalcode
Problem 172 can be done by hand.(As shown in the private forum.)

Re: Paper/Pencil Problems

Posted: Mon Oct 15, 2012 2:23 am
by dianopoulos
#31 and #72 I did by pencil and paper. Does this mean I'm a computer? o.O

Re: Paper/Pencil Problems

Posted: Fri Jun 07, 2013 9:24 am
by Gnomy
I solved 43 by hand , So it too can be added to the list
http://projecteuler.net/problem=43 :D

Re: Paper/Pencil Problems

Posted: Thu Jun 27, 2013 7:49 pm
by GenePeer
Problem 188 (View Problem). Nice to stumble on one after a year-long hiatus.

And Arancaytar mentioned solving Problem 282 (View Problem) on paper.

Re: Paper/Pencil Problems

Posted: Fri Jun 28, 2013 9:12 am
by chekellog1010
garethrees wrote:Here are some that I think are solvable using paper and pencil:

Problem 1 — basic summation
Problem 2 — journeyman summation (Concrete Mathematics has a good chapter on this type of problem)
Problem 5 — easy
Problem 6 — more summation
Problem 8 — by inspection, if your eyesight is good!
Problem 15 — find the formula
Problem 17 — find the formula
Problem 18 — tedious, but only 120 steps, and the arithmetic is easier
Problem 19 — a very rough estimate might work out, you never know...
Problem 24 — much like long division
Problem 25 — might need a calculator once you've worked out the formula
Problem 26 — only need to examine a few cases, though the long division will be very tedious
Problem 28 — summation again
Problem 40 — easy
Problem 63 — only a few cases to check
Problem 69 — obvious once you see it
Problem 76 — just about doable, I think, with a Grundy scale (cf. Winning Ways)
Problem 79 — easier to do by hand than by computer!
Problem 85 — just about doable with the right formula and a good search strategy
Problem 97 — if you don't mind a lot of tedious multiplication (and you've read section 4.6.3 of The Art of Computer Programming!)
Hi garethrees,
great solutions, i may use of these on my class ad i think it can be a good for me as a teacher,

thanks alot :-) che

Re: Paper/Pencil Problems

Posted: Sun Jun 30, 2013 12:18 am
by GenePeer
Problem 190 (View Problem)

Re: Paper/Pencil Problems

Posted: Sat Jul 06, 2013 12:17 am
by Rainy Monday
Problem 169 (View Problem) with the right formula.

Re: Paper/Pencil Problems

Posted: Sun Jul 07, 2013 8:06 pm
by GenePeer
Rainy Monday wrote:Problem 169 (View Problem) with the right formula.
Interesting that I just recently revisited this problem to remove my use of BigInteger; it didn't occur to me.

Re: Paper/Pencil Problems

Posted: Thu Jul 18, 2013 12:55 am
by GenePeer
Problem 182 (View Problem) - reminiscent of P001

Re: Paper/Pencil Problems

Posted: Mon Jul 22, 2013 10:39 pm
by Rainy Monday
#336 seems to be one.