New Solver!

Now the theory is complete!


Check out the new solver which gives no gimmick solutions. Pretty much all solutions are reasonably distinct. Except solutions like 4 * 6 *7 / 7 and 4 * 6 + 7 – 7 are treated as distinct solutions.

I think it’s debatable if they are different and I will just leave them as is.

Will update all other pages to reflect the completeness of the solver.


Edit: On second thought, 4 * 6 * 7 / 7 and 4 * 6 + 7 – 7 should be treated as the same solution, will finish this over the weekend.


CSS float

If you view the site on your Chrome/Safari/Firefox browser, you see what the site is designed to look like. IE on the other hand, acts up on my CSS file (which is stolen from nearlyfreespeech).

Tried a couple of things and gave up. My hack on the problem is to change all the floating objects in the CSS to fixed positions.  So, go download a Chrome or Firefox browser. IE blows.

Almost done, I will redirect the ocf.berkeley links here over the weekend.


The site

I have been researching for the right webhosting service (and domain registration all that) for a while. Of course with the SOPA drama, Godaddy is the first thing that I would not consider.

After reading a bit of the comments on reddit,  I was convinced that  nearlyfreespeech might be worth trying. So far so good. And I actually like the layout on their site. And I have hence used their css file. So don’t be surprised that 24theory looks just like nearlyfreespeech.



I first played 24 the math game in 1984, I think.  The way we played was that we randomly pull out 4 poker cards and winner takes back all the 4 cards.  The one with all the cards at the end wins the game.  So it’s great for 2 or 4 players, we need to modify the rule at the end when less than 4 remain in the game.

It is a great way to draw kids into maths, science and other good stuff.

Fast forward to 2009, my then girlfriend and I played again to kill some time in boring New York. As someone with some street credit in maths, I found myself constantly beaten by my girlfriend. Frustrated, I decided to code up some perl script to solve the game for me. This was hosted on Not satisfied with the original solver which only gives a solution (1x2x3x4 for the quadruple {1,2,3,4}),  I coded up a script to give all possible solutions with some redundancies reduced: (3+2+1)×4,  (4+2)×(3+1) and 1x2x3x4.

Note: given  1x2x3x4,  4x3x2x1 is considered a redundant solution.

There are still more work to be done. For example, given quadruple {1,3,6,10}, my current solver gives 3 solutions: 10×3×1-6,  10×3-6×1, (10×3-6)×1.

They look different topologically, but they are all just 10×3×1-6.