Apple is celebrating the life of a college student so they’re giving away one education-themed app each week via the official Apple Store client for the iPhone and iPad.

Although some other promo offers are available only to Apple Store visitors, anyone who has downloaded the free shopping app to their device and has a U.S.-based iTunes account can now download Tydlig for free.

Note that these promos are separate from Apple’s ongoing Free App of the Week so iOS apps which go temporarily free in the Apple Store app still cost money when accessed regularly in the App Store via their iTunes links.

In the past two weeks, two high-quality apps have gone temporarily via the Apple Store app (not to be confused with the App Store): the gorgeous Rise Alarm Clock and Runtastic Pro, a premium version of the popular fitness tracking software.

If you love calculators, the advanced Tydlig for the iPhone and iPad will be free until next Wednesday, a $2.99 saving.

Here’s how you can redeem your free copy of Tydlig…

Previously highlighted in the App Store’s Productivity Monday feature, Tydlig by Andreas Karlsson is an ingenious calculator for iOS. The uniquely designed freeform calculator makes it dead simple to reference previous calculations by tying any operation to a result, creating a dynamically updated value.

Being able to drag numbers around and see how graphs change as you use the slider can be a very enlightening way of learning, according to developers, because it reveals the “beauty of the relationships” between numbers and gives an “intuitive feel for math, rather than focusing on the tedious manual labor” usually required in class.

Of course, you can change any of the values and the updated results will cascade down these linked numbers.

As Apple explains:

This week work with Tydlig, a calculator reimagined to help you with everything from tips and discounts to real-time graphing. Work smarter, not harder by referencing your previous calculations, and share your work by printing or exporting results as a high-quality PDF.

In addition to freeform canvas, responsive results and linked numbers, Tydlig includes other great features, too, such as real-time graphing, value annotations, undo, Bluetooth keyboard support, fast calculation engine, over 20 mathematical functions and scientific notation formatting options and much more.

And here it is in action.

To learn more about Tydlig, check out our mini-review.

How to redeem your free copy of Tydlig

Step 1: Download Apple’s official Apple Store mobile app to your iPhone or iPad free from the App Store. Fire up the app, tap the Stores section and choose any retail store under All Stores, or search for a specific store (i.e. ‘Fifth Avenue’).

Once you land on a store page, look for Tydlig halfway down the section.

Step 2: Tap the entry and up pops a prompt offering a promotional code for the calculator app. Now hit the big green Download now for free button at the bottom.

Step 3: Doing so will yank you out of the Apple Store app and open the iTunes app. Upon signing in with your Apple ID, you should be able to redeem the code.

Step 4: If all goes well, your download will begin automatically and you’ll seed a confirmation message like this. Note that this offer requires that you redeem Tydlig with a U.S. Apple ID, iTunes Store or App Store account.

But don’t worry, iDownloadBlog has you covered — simply create yourself a US-based Apple ID account without a credit card and you’ll be able to download apps, music, movies and other free iTunes items.

Be sure to check back next week as a fourth and final college-themed app goes temporarily free, hopefully helping you get more from your iOS device, in class and out.

In the meantime, do yourself a favor and grab Tydlig now.