Comments on: Solving the Four Fours Puzzle

By: Julian

Julian — Wed, 31 Mar 2010 03:51:23 +0000

Jennifer,

Presumably by 4(2) you mean 4², which is not allowed.

44/4=11. (I am not adopting the “exactly four 4s” rule.)

By: jennifer

jennifer — Wed, 31 Mar 2010 00:56:56 +0000

11. 4(2)-(4/4+4)

By: POPSTAR5000000

POPSTAR5000000 — Sun, 05 Oct 2008 16:29:21 +0000

AGHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH help! lol. my teacher set this for my whole class to do as homework
when I went to school not long ago. I just thought that I’d refresh on all of this but there’s so much to remember, and the computer symbols are extremely confusing. I hated that teacher! Anyway I think that Katie’s comment may be wrong, as she doesn’t always use four fours which is the aim of the puzzle. Anyway, have fun working this horrible stuff out. xD

By: smirg

smirg — Tue, 16 Sep 2008 03:18:24 +0000

nerds

By: Katie

Katie — Tue, 22 Jul 2008 20:43:02 +0000

1=4/4
2=√4
3=√4+(4/4)
4=4
5=4+(4/4)
6=4+√4
7=4+4-(4/4)
8=4+4
9=4+4+(4/4)
10=4+4+√4

By: Julian

Julian — Sun, 02 Sep 2007 12:08:42 +0000

So what ever happened to this program? Well, it appears my software is still buggy, because the 9th cycle (i.e. working out formula that ar 9 digits long) took 2130 times longer than the 8th cycle, rather than the expected 8-10 times longer +/- 50% error bar due to other CPU loads.

I aborted it after the 9th cycle completed, and haven’t got back to it this week to work out what went wrong.

By: Julian

Julian — Sun, 02 Sep 2007 12:04:34 +0000

Aristotle,

A minor consideration when defining concatenation as a simple function – it is a function that only takes digits (or the results of the concatenation function) as an argument. You may not pass the result of another expression to it. This was something minor I had to handle when coding.

By: Julian

Julian — Sun, 02 Sep 2007 12:02:34 +0000

John,

Your arguments against concatenation and/or the rephrasing of the problem are all valid. It is funny that I just assumed its validity to begin with. It seemed natural to me.

(I didn’t even begin to consider the different bases, as Aristotle suggests.)

I share your distaste for the repeating decimals.

By: Julian

Julian — Sun, 02 Sep 2007 11:49:55 +0000

I've added cite to q tags. The cite attribute is allowed on ins tags. (Will anyone ever seriously use that tag in a comment? I doubt it!) I would like images permitted in comments - e.g. the Man In The Moon article could have people submitting their own pictures. However, it leaves open the question of who hosts the pictures. Also, if I was a spammer, I would be actively seeking sites that allowed the posting of pictures in comments.

By: Aristotle Pagaltzis

Aristotle Pagaltzis — Sun, 02 Sep 2007 09:45:28 +0000

Very nice!

Nit: it says and ; I think you wanted to allow the cite attribute on the latter, not the former.

I don’t know why these tags are not permitted on a default install either. I can’t think of any effect either other than discouraging properly structured long comments – surely that’s not a goal? No images is just fine with me, btw, as is no tables. But lists are essential – and they’re allowed now, finally! The current lineup seems pretty complete in terms of common markup; off hand, I can’t think of any tags I might miss.