This game is still in beta. The first area is complete, but the second area only has a sandbox and 3 demo levels.

Welcome to the world of Factor Crafter, where elemental stones obey the laws of multiplication. Prime numbers form the basic elements, and can be combined together to create composite stones. Your job is to craft and dismantle composites (like 54 and 98), make two stones match, find common factors, and even estimate logarithmic size of stone "logs".

Fill up your almanac as you multiply Prime Gems and factor Composite Stones, building your understanding of prime factorization and related concepts.

Features: 23 levels, an almanac of 100 stones (in-progress), and two Sandbox levels.

Includes preview of: Lowest Common Multiples, Greatest Common Factors, logarithms, and algebra. More will be available upon release, by purchasing the full game.

Possible Future Features: Teacher's guide, additional games, visual tutorials. Let me know what other features you want!

Accessibility: Sound is optional. No time limits. Mouse-only. Strong English-reading ability is ideal, but not required. (Some students like figuring out the game via experimenting; others like reading the tutorials.)

U.S. Teachers: This game covers most of common core standard CCSS.Math.Content.4.OA.B.4 (4th grade), plus some introductory algebra concepts. The full game will eventually cover CCSS.Math.Content.6.NS.B.4  (6th grade), and have optional logarithm levels. It is great for middle school students just learning about factors and multiples, and is also a good way for high school and college students to gain a better understanding of exponents and logarithms.

Credits: Design and programming by Jeremy Hoffman (hoffman.jeremy98 [at] Graphics by Trista Paul (tristagpaul [at] SFX from,, and

Install Instructions:

WebGL (Browser, Chromebook) Extract files, then open "index" file to run in web browser. [This has not been tested on Chromebooks, but I think it works.]

Windows PC: Extract files, then open "Factor Crafter" executable file to run.

Android: As this game is not purchased from an app store, you may be warned that the file is "not from an authorized source", or "potentially unsafe". You may need to  edit your settings to "install apps from unknown sources". The installable file is stored in your "Downloads" folder. Do a web search for 'install apk on [your Android device]' for more information.


Factor Crafter 0.9.0 - Android.apk 39 MB
Factor Crafter 0.9.0 - 30 MB
Factor Crafter 0.9.0 - WebGL (play offline in browser).zip 20 MB

Development log


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I LOVE this game. I really enjoy how you taught me all these cool tricks about prime numbers. Yet, still making it fun. This is one of my favorite games!!!

Thank you! Glad you enjoyed it! I'm currently working an adventure/card game set in the same universe, though it could take a while.

I'm already excited!!!  Have a great day.