A downloadable game for Android

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I bet your high school math teacher told you that you'd never need to know math because you'd never use it in your daily life. This game is here to prove your teacher wrong, provided you play it every day.

In order to pass each level, you have to get as many points as are stated in the level's goal. The way to get those points is by constructing mathematical expressions out of the falling blocks. But this ain't no ordinary elementary school arithmetic. This is modular arithmetic, a slightly different animal.

Each level will have a target value that your expressions must equal in order for those blocks to disappear. The target values are expressed in the form "x mod n" (for example, 3mod7). What this means is that your expressions must be equal to a number that is x more than a multiple of n. In the 3mod7 example, you want your expressions to equal ...-4, 3, 10, 17, etc... Once you construct an expression that equals a member of 3mod7, the blocks in that expression will disappear, and you will be awarded a certain amount of points based on the operators used in your expression. You can also make use of variables. If your stacks of blocks get too high, you lose.

Be sure to check out the tutorials in the settings menu for more about how the game works. While the math may seem unfamiliar or difficult (at first), there are tons of clever tricks you can employ to make it simpler and faster. Find many of these in the tutorials. Discover some on your own. And, of course, practice makes for slight improvements. 5 levels in and you'll wonder how you ever lived your life without modular arithmetic. 10 levels in and you'll realize that you haven't actually lived your life without modular arithmetic; it's been all around you the whole time. Woah.

You will also find the short and long tutorials available for download on this page. Download them and give them a read. Maybe they will induce flashbacks to your SAT prep courses.

Many challenging puzzle games promise some sort of improved general cognition or overall brain-training effect. Not this game. This game is 100% guaranteed to make you better only at modular arithmetic (provided you weren't already good at it and that you play it daily and learn from your mistakes, local restrictions apply). However, it certainly does feel like your brain is doing yoga on a bicycle going uphill against the wind when you get to the harder levels.

Levels 1-35 are a straightforward progression of increasing difficulty, with lower loser-bar, fewer blocks visible on deck, ever-increasing block speed and ever-increasing n (from "x mod n") with each level. Levels 36-50 are a series of lightning rounds. N is always under 10 but the speed is much higher, the loser-bar is really low and very few blocks are visible on deck. Beware!

For some levels, n is fixed, but for many others, n is randomly chosen to be within a certain range. And for all levels, x is randomly chosen to be between 0 and n-1. This means that even if you manage to beat the highest level and "win" the game, there is still a ton more challenging gameplay to be had and a huge variety of unique levels. In level 30, for example, n is chosen to be between 2 and 99 and x between 0 and n-1. Just because you beat level 30 for 8mod27 doesn't mean there aren't many more variations of level 30 to beat. Exactly how many variations of level 30 are there?


android.permission.INTERNET - This app doesn't actually go on the Internet. The tutorials are local .html files and the Internet permission is required to display them.

android.permission.READ_EXTERNAL_STORAGE - To read and modify app settings

android.permission.WRITE_EXTERNAL_STORAGE - For storing gameplay screenshots

More information

Published1 year ago
Tagsarithmetic, condescending, group-theory, intellectual, logical, math, modular-arithmetic
Average durationA few minutes
Player countSingleplayer


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Click download now to get access to the following files:

Modulo.apk 1 MB
longtutorial_itch.html 6 kB
shorttutorial_itch.html 1 kB

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