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Show HN: I made a little math game named Summle (summle.net)
189 points by kirchhoff on March 4, 2022 | hide | past | favorite | 78 comments
I made this game for my children to play, as they are heavily into Wordle, and I thought they'd also like something maths based!

Every puzzle is solvable and has at least one solution (usually more).

There is a kids mode in the settings, plus a hard mode for extra difficulty.

> I made this game for my children to play

Mathematician here. It's fun, but it's quite hard! How old are your children?

[spoiler alert?]

I finally solved it in 4 steps. It needs a lot of backtracking planning. I has to guess which will be the last expression and try to reach the numbers that it used.

I don't play too much Wordle, but my approach was just trying to find a word that is not to stupid (like reusing a lot of letters that are already grey) and just hopping that that the new info will make the next step easier.

> It needs a lot of backtracking planning. I has to guess which will be the last expression and try to reach the numbers that it used.

I ended up creating a mental factorization table of the target number with only the available numbers as factors. That pretty "quickly" lead to a solution in only three steps.

I put the "quickly" in scare quotes because I essentially brute forced the problem.

I'm pretty sure this is the only way to solve it (factorization table). I don't see how else?

Hard? I found the hard one fairly easy, and don’t think I accidentally spotted the solution early. For difficult, I would expect at least one division, as in (ax+b)/(c-d)

But yes, I factored the result in my head. I would have done the same with (result ± any of the other numbers), if necessary.

Also, for the simple one, I immediately recognized 243 as a power of 3, so maybe, I’m not in the target group ;-)

I'm still working on the difficulty levels. I think recognising factors of either the target number or nearby numbers is key.

I found it hard to. But it didn’t plan, I was going kind of trial and error. I found this 4 steps solution after certainly more than 50 tries

There is a kids mode in the settings. Today's one is hard, I must admit (though it can be done in 3 steps) - they did well when I was testing the site!

Inspired by Countdown? Been a while but don't they have 6 numbers? Might be nice to allow users to choose "2 big and 4 small" as well.

That's what I thought of too. Even though Countdown is kind of the UK version of the longer running French game https://en.wikipedia.org/wiki/Des_chiffres_et_des_lettres#Nu...

Yup I immediately thought about the numbers challenge in that French show I watched as a kid

Indeed. Everything old is new again. There should be 6 numbers - perhaps one is cut off. Are you on mobile?

Write a bot to play countdown: https://botfights.ai/game/countdown

Countdown can actually get quite difficult too. Since you have the 30s timer. I learned a lot from Rachel’s solutions.

I'd pay good money to play Summle 2.0: Jimmy Carr insults you before you start playing.

Quite hard dude! I'm still going at it. Once you put down an equation like 100x3=300, your mind becomes committed to it...which biases your future choices & quickly leads you down the wrong path. Awesome game. Pls compile stats on average solve time. I'd be interested to know how long it takes to solve the daily summle on average (aka how dumb am I compared to rest of population )

You have +,-, * ,/. But no ^. Why ?

I used to ask a^b * c^d=abcd as an interview question. In most programming languages its a 4-line nested loop to find the unique solution.

It becomes much easier once you factor the number, rather than trying to narrow in on the answer

Light spoiler: gurer vf n fbyhgvba juvpu qbrf abg hfr bar uhaqerq

That's true if the solution is a product, not a sum.

Start with the product solutions, and if nothing seems pliable, start backwards and work with the sum results.

For the hard one, 612 is not an easy number to find, but basic math shows that 6+1+2=9 so the number is divisible by 3 (and I won't go any farther to prevent spoiling it) Finding a system by which you create the situations that allow the operands and factors to be discovered while also flexing your basic math skills is the fun of the game.

re 612, gjryir unf znal snpgbef fb fvk gvzrf uhaqerq znxrf sbe n avpr erznvavat qvfgnapr

Fvk Uhaqerq nyfb unf znal plcuref ohg fbyivat jurer gb trg gur guerr sebz vf gur ovttrfg pyhr

^ seems like it would get spaghetti fast - multiplication's already not easy to visualize and something like 12^6 which involves two numbers that are 'low' by the game's standards, becomes a ridiculously high number. I mean might as well add some other operations if you'll do that right?

I wanted to keep it to operators everyone would understand, though it would be interesting to use exponents!

I am only recording successful attempts, which for the regular puzzle is around 33% so far today. I might compile stats on solve time too.

Nice, very similar to countdown. If you've not seen it then '8 Out of 10 Cats does Countdown' is a great comedy version of the classic show on Channel 4 in the UK.

Nice work! The Countdown model works well for this format. Best maths Wordle variant I’ve seen so far. The video really helped to see what to do (minor point: had to scroll down to see numbers on my phone). Did feel a little cheated when my iteration was locked in as a solution and I could immediately see an improvement!

Thanks for the feedback. Re: the scrolling issue - can I ask which device?

Pretty fun, few comments 1) The Share Results currently includes a few spoilers as it shows that the player has included the result of one of the previous steps. This makes it considerably easier for someone to get the answer. https://imgur.com/a/frGcWtL

2) It does not appear to remember your game if you close the browser and return as wordle does. The solution you entered is then hidden. https://imgur.com/a/IEFRFnT

it would be nice to be able to get back to this screen once you've completed it even if you close the browser https://imgur.com/a/DDkF7On

Thanks. The 'share results' grid is about as minimal as I can make it without it being devoid of information!

The reset upon completion is intentional, as there is (usually) more than one solution to be found. For the purposes of stats recording, only the first successful attempt is registered.

nice! instant throwback to childhood watching Des Chiffres et des Lettres on TV

a bit of feedback, can you make it so that if you type an operation on the first block of a line it takes the last result as the first item and fills the op as the second item?

the thing that trips me up playing is thinking like:

"50 plus 3 is 53, minus 7 is 46, times 3 is 138"

so I'd type 5 + 3 - 7... i.e I press the operation right away instead of typing the last result before the op... oddly frustrating! and I keep on doing it over and over again!

oh, and I second the request to clear the board, reloading just doesn't cut it: it's a full, slow enough RTT to the server that I type on all inputs to clear them up instead. plus when added to the home screen as a web app on iOS there's no way to reload except killing the app... a bit frustrating also!

Yeah. I said « le compte est bon » to myself. I’m not specifically math inclined and I had fun playing.

Nice. Summle seems a bit easier to get into than https://nerdlegame.com

Nerdle works like Wordle. This works differently.

You can burn yourself early by doing an incorrect equation, and the only way to finish is to reset by refreshing the page.

So it is more of a learning game then a competitive/iterative game.

You could do it all in your head (or in another program/on paper) to do it the best way on your first try, but you can't fix mistakes once trying something teaches you something.

You can click on numbers to remove them, so that you do not need to refresh the page.

I find nerdle easy. always 23+45=68. (only missing 0,1,7,9,-,*,/) so in one test, touched 8 of the 15 possible characters.

Nice one and an interesting twist from the classic Wordle. If I may one small suggestion, please add a clear and/or backspace button. Like the buttons present on most real calculators: CE (current entry), C (clear), AC (all clear). I know that you can click on an occupied cell and clear it, but backspace is more convenient :-)

Thanks. The backspace is something I considered, but it would have to function more like an undo button. You can refresh the page (or click the logo) to clear all the cells.

[Spoiler alert] Terrible brute force program in JS says there is (possibly, didn't prove it) 6368 different solutions: https://gist.github.com/mvladic/9b2f2025a8c54aca78649ce17766...

How many if you filter out trivial permutations?

I found a "normal mode" solution in a couple minutes after some trial/error. But then I spent 10 minutes trying to find a solution in "hard mode" to no avail. I ultimately gave up and wrote a recursive solver in python. Now I feel better about myself and can continue about my day.

I really like this and find it much more engaging than mathler, which is my current favorite (nerdle doesn't really do it for me).

The difficulty levels seem right for my level at least - kids mode was almost instant, regular took a bit of thinking, advanced still has me stumped:(

Please consider a "clear all" button. I know you want to keep the UI simple and that I can refresh the page, but this seems like an omission considering how much trial and error I'm doing on advanced mode.

Also, maybe an "I give up" button, hidden somewhere in a modal. I suspect I'm not going to have time to solve this before the next puzzle comes along, but I still want to know the solution.

Consider a mode with limited uses of the operations too. I liked it, but I thought both normal and hard modes were too easy given I didn't have to think about what operation I was going to use at all.

#Summle #7: 3/5 = = =

I like it. Some UX tweaks would be nice, maybe an undo, a clear all, and perhaps some helpful focus shifting (of which tile is being intended for a click) depending on context.

Another thought, having an in-app calculator (so one could free calculate factors of an arbitrary number) might generate interesting data to see the approaches your users take? I could see how that might be interesting data for cognitive mathematics research.

The undo function is in the works.. to clear all you can refresh the page (or click the logo). There is an effect when a tile is filled but perhaps it needs to be more dramatic.

This is brilliant, but impossible to learn how to beat on Hard mode without programming brute-force recursion. Even when we factorize the target number and its neighbors.

a) Can you publish daily solutions to yesterday's problems? I'd really like to see the solution to #8-Hard (1,6,7,7,50,100 Target: 875)

b) Can you add links to archived previous problems?

Well hello. I was in the middle of making a game with a very similar premise lol, apparently a few of those are around, but I do think the Countdown gameplay of 6 numbers is 'too difficult', you can't make poor guesses and still win like in Wordle.

How does the "app" feature work? Was it easy to make (given a static site)?

To make the site work as an 'app' you just need it to conform to the PWA (Progressive Web App) guidelines, and handle the install prompt. There's a good guide here:


Nice, thank you. That's a nice feature that I didn't know about.

I clicked through and then immediately forgot the instructions so I tried to go back to read them. Now the button just says "Come back Tomorrow" and I can't even play. Stopping a person from playing again does only bad things for user experience. Please consider just not doing that instead of doing that.

I think you meant to post in the thread about the emoji game?

You are correct! Thanks!

I got the answer on the first try in 5 steps but I felt like I was a bit lucky. Reminds me of playing 24 and Krypto.

Wasn't that into it. I couldn't feel the connections as easily as Wordle between the incremental guesses.

It's not meant to have the same type of connections as Wordle, even though it looks like it.

You can't just randomly put in a combination and then use it or get info.. you really need to plan the whole thing out before doing anything.

Actually, it isn't that hard (took me about 5 minutes to arrive at the 3 steps solution). Especially with a number like 486 which you might have met in school, when learning multiplication... Then again, I like the mental exercise :-)

Edit: And another 6 minutes for the 'hard' version (4 steps).

I think I was a bit lucky, but solved today's (#8) optimally in a minute or two.

Pretty cool puzzle, reminds me of this: https://blog.plover.com/math/24-puzzle.html

#Summle hard #8: 5/5 = = = = =

Is "hard mode" based on difficulty judged by a solver? It feels like something that would more easily differentiate the modes would be adding extra numbers instead of 6 for all modes.

It was not clear to me that "the" solution didn't require all the tiles.

Or that there were multiple solutions.

In the end, I did all the steps in my head, and then refreshed the page to do it in 3 steps.

But it's not really an "iterative" game.

The rules are on the info page - maybe not that obvious.

Yup - I skimmed them, so that's on me! Don't let me being relatively harsh discourage you.

It's a good, educational game that makes you think. It just feels very different from something like Wordle, and that's OK.

Now that I got the hang of it, I tried the easy and hard modes as well, and got them both on the first try without having to undo anything.

But as others said, I looked at the available numbers, figured out what I had to multiply to get close, what I'd have to add/subtract to get the rest of the way, and how I'd use the leftover numbers there to make the addition/subtraction possible.

Basically I brute-forced it in my head. But I think it would be enjoyable if it somehow felt more iterative, and less like I was working from the solution backwards, and then just filling the steps in all at once.

Thanks, all feedback is most welcome. I tested it with only a small number of people.

#Summle #7: 3/5 = = =

This did not come naturally for me. Spent about 30 mins on it. After a long time, I opened my calc app and worked backwords. From there it only took a few mins..

EDIT: hints might be nice to make it more wordle like

Today's puzzle was difficult I admit. It's tough to find a balance, I'm still working on it!

Got very intersted, then lost interest because I couldn't reload and get a new number when I was sure I had taken the wrong path. Is there a feature to start again from a new random number?

I built one less challenging in Java some years ago.


Looks a lot like https://c.eev.ee/digitle/

This is great!! I have to fit it to my screen a few times. But now I know how to fit it to my screen it’s fun!!

Can I ask which device you're using?

Iphone SE and on Firefox.

Took a while, solved kids mode^^ I suck, thanks for rubbing it in. Incremental difficulty?

Love it - did both the regular and the hard mode. You should add a fiendish mode!

Thank you. I do actually have another mode planned!

I’m a kids mode type player.

You won't like the extreme mode I have planned.

Me too. This game definitely did not come naturally to me. I could only brute-force it and backtrack.

Could you maybe provide a times table for help?

I am enjoying this, thank you!

with this game, you can entirely solve it on paper - which is cool as hell


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