I once thought developing mobile apps insurmountably hard. Not true, especially for simple apps that looks and feels like webpages. I pickup phonegap as the platform and wrote the apps like writing web-games.

I put my hands on mobiel app development in March 2013, and by September, all 12 apps are int the market. That is 3 core apps X 2 X 2, where the first X2 is English/Chinese, the second X2 is android/IOS. So check it out. It’s all free.

The apps are on this page:

List of all math 24 games on 24theory (II)

This is the second part of “what’s new with 24theory”.

1024test: you want to know how good a math 24 player you are against other players? Take this test. We will give you 10 math 24 puzzles (hence 1024 the name), each of a different difficulty levels. We’ll give you a score telling you how good a mathlete you are. It has been recently incorporated into our solo game. After finishing each solo game, we give you a “1024 score”, 100 being the greatest player ever and 1 being the worst.

Live game: you want to play math 24 game in real time with people from around the world? Try this. We send out a new game at the beginning of every minute. You solve it, we record the time. And at 45 seconds of that minute, we rank all submissions. And you can see your rankings in a real time fashion. The live game has rapidly become the most popular game on 24theory. It’s truly addictive.



List of all math 24 games on 24theory (I)

In the past year, I developed several new games in addition to the original solo game.

Math 24 challenge mode: in this game, you can play 5, 10 or 20 puzzles then send the resulted link to your friends. Your score is encrypted in the link. After your friends finish the same puzzles, they can see both scores and know who wins. If you choose to, you could get an instant email with the results. This is great for teachers to assign math 24 puzzles to students.

Kids’ 24 game: in this game, we only allow puzzles  that can be solved without divisions and/or multiplications. It’s a great beginner game for kids to learn basic additions, subtractions and multiplications.

Alexa top 1,000,000

Started a year ago. First, just the solver, then the single-player game, then the challenger game, twitter/facebook daily game.

Now it’s one of the top 1 million sites on the internet according to Alexa. I know it’s a small step, but still. Quite happy about what has been achieved.  Alexa top 100,000, here we come!

Check out the stats:


After several weekends’ of work. Now you can play 24 the math game here.

Have fun and make it to the record books!

Hopefully I will collect enough data to rank the difficulties of the 1362 puzzles.


now go play!

Letters like this motivate me

I recently got an email titled “Great Site !!! ” Emails like this make me want to put more effort on math 24 game and put more content on this site.  With Manuel’s content, I post the edited email below:

Hello, my name is Manuel, i am from Barcelona, Spain.

First of all  would like to thank you for all the information i got from your site.

24 is a great game a friend of mine teach me two weeks ago.

I am just learning Java and coded the game. Brute force algorithm building all permutations given for numbers, adding all permutations for signs and finally adding all possibles parentheses. Then evaluating each possible solvable. Founding all solutions.

In the other hand in Rosettacode page i looked carefully all codes, (did not found Java which really surprise me)  but what surprise me the most was that all codes there, work like mine, brute force.

I will continue in summer, after my final exams, trying to do my best with the algorithm.

Keep this nice site up.

Cheers !!

Difficulty level of a quadruple in 24 math game

Given two quadruples, say (1,2,3,4) and (7,8,9,10), which one is easier for a human to get a solution?

Looks to me 1,2,3,4 is fairly easy, 4×3×2×1, meanwhile, 7,8,9,10 is solvable with  9×8/(10-7) , but slightly more difficult in my opinion.

Turns out (7,8,9,10) has only one solution shown above, while (1,2,3,4) has three distinct solutions  (3+2+1)×4, 4×3×2×1 and (4+2)×(3+1).

It seems to me there are three factors that decide the difficulty level of a solvable quadruple:

1) number of solutions, the more the easier.

2) type of operations, I cannot say for sure that the order from easiest to most difficult is + – × /, but I know 13/7 is as hard as it comes.

3) size of the numbers, the smaller the easier (it’s easier to do 4 + 3 than 13 + 7, slightly)

Obviously the best way to really figure it out is to develop a game, let millions of people play and collect their reaction time to each quadruple. That’ll be awesome and probably my ultimate goal.