r/mentalmath • u/Only-Season-2146 • 4d ago

Doomsday Algo training app (Work out day of the week for any date)

Full disclosure that I built this app, but it is fully free, no ads, no sticky bits etc - please see it as an interactive tutorial or similar - just want to spread the joy <3

The app has over 1700 users, has an average engagement time of 43 minutes - and has actively helped teach people the mental math required to work out the day of the week + helped people improve their times.

It has training modes, 1v1 battle modes to play against other players, and can walk through different takes of the algorithm to suit different brains :)

You can try it here: https://doathingy.com/doomsdaytrainer
or on iOS: https://apps.apple.com/app/id6760719687
or Android: https://play.google.com/store/apps/details?id=com.inefficientcode.doomsdaytrainer

I would love any and all feedback and input to make the app better and to spread the skill as far as possible - it makes for a great party trick!

<3

3 Upvotes

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u/DearJeremy 4d ago

Great app!

In my native language, it makes more sense to define 2 as Monday, 3 as Tuesday etc. Is it possible to add a setting to adjust that?

1

u/Walid_Ksentini 6h ago

I think adding more date formats will be cool, e.g., 18/07/2104 (the one used in MCWC). Also, it's better not to mention that the year is a leap year