Today’s apps gone free: The Math Keyboard, Sleep Pillow, OTTTD and more

Write equations, create a relaxing environment, and fight off foes with towers and heroes with today’s collection of apps and games.

All app prices are subject to change at any time and without notice regardless of stated free duration. Price changes are solely under the control of the developers.

Universal:

OTTTD ($0.99 → Free, 112.3 MB): Eradicate your enemies by deploying towers and heroes in OTTTD. Fans of tower defense games are sure to enjoy this one.

An inter-dimensional rift has been opened in order to bring odd creatures to Earth and provide out of work soldiers with something to do. Defend your post by placing powerful towers in strategic positions, and command squads of heroes to clean up what’s left. After each battle, you’ll be able to level up your heroes and unlock devastating new weapons. The game also includes some snazzy graphics, which allow you to cover the battlefield in giblets.

OTTTD is available for free for a limited time. It has a 4.5-star rating with a total of 542 ratings.

The Math Keyboard ($0.99 → Free, 26.5 MB): This third-party keyboard puts math and scientific characters at the tips of your fingers. It’s the perfect app for students and anyone else who constantly deals with equations.

The Math Keyboard allows you to quickly write equations and share them however you wish. After adding The Math Keyboard, just tap the globe button to bring it up. The keyboard’s seven different character categories can be accessed via the row at the top. Some categories have multiple pages, which can be accessed with a right to left swipe. The Math Keyboard works great in all native and third-party apps.

The Math Keyboard is available for free for a limited time. It has a 4-star rating with a total of 42 ratings.

Sleep Pillow Sounds: white noise machine app ($1.99 → Free, 286.0 MB): Fall fast asleep with Sleep Pillow. It creates a relaxing environment.

Sleep Pillow features a collection 70 naturally recorded sounds that can be mixed and matched to create more than 300,000 combinations. You can also add sounds to your list of favorites for quick access later on. The app includes a sleep timer with fade, high quality images, and background audio support.

Sleep Pillow Sounds: white noise machine app is available for free for a limited time. It has a 4.5-star rating with a total of 11887 ratings.

Week Agenda Ultimate ($0.99 → Free, 3.6 MB): Keep your schedule straight with this gesture-driven productivity app. It’s ideal for those who want to focus on life one week at a time.

It displays all of the events on your calendar in weekly clumps. Just swipe to turn the page and view upcoming or preceding weeks. Create new events by tapping and holding on a day, and edit events by tapping on their titles. You can also tap on a day’s title to enter the daily calendar view. The app includes the ability to jump ahead months and years with two and three finger swipes, and jump back to the current week with a long press on the top of the page.

Week Agenda Ultimate is available for free for a limited time. It has a 4-star rating with a total of 212 ratings.

That concludes today’s issue of Apps Gone Free. If you like staying on top of these daily deals, don’t forget to check out our free AppsGoneFree app. It provides all the deals each day, and even an archive of past deals that are still active.

Developers:

If you are a developer who would like to get your app included in our “Apps Gone Free” daily lists, here’s our basic set of rules:

It must have at least a three-star average rating at the time it goes free.
The app must not have been free numerous times (3+) over the last six months.
The free version of your app must not include ads.

To submit an app, simply send a request to tyler@appadvice.com with the subject “Apps Gone Free.” Please include the name of the app, a link to it in the App Store, when and for how long you intend to offer the app for free, and anything else you would like to share. We will take it from there.