Today I learned that the iPhone’s built-in calculator app has a scientific mode — and all you have to do to access it is turn your phone on its side. If you’re the type of person who keeps your phone permanently in portrait lock (like me), this might come as a surprise to you, as it did to many of us here at The Verge.

This unlocks all sorts of functionality, like adding numbers to memory, parentheses, exponents, and all those trig functions from back in high school. The feature isn’t exactly new, or hidden: It was introduced in iOS 2.0 back in 2008, and there’s actually even a screenshot of it on the App Store page for the calculator app.

To be fair, most people probably never see that App Store page, as the app comes pre-installed on every phone. It’s not the first app that you’d probably look for if you wanted to install a new calculator, either — even with the hidden(ish) functionality, it’s still not great.

For starters, there’s no ticker tape feature, which lets you see all the operations you’ve just done, which is useful when you need to see if you’ve already added a value or not. It also makes some essential functions like parentheses — which I use in almost every math equation I do — hard to access.

Thankfully, there are other options: PCalc offers a more robust calculating experience, and offers a free PCalc Lite version that’s also worth a download. Or for more serious math, there’s the TI-30XS, which can make some things (like fractions) so easy it almost feels like cheating.