The Calculator app on your iPhone may seem boring and basic, but there are a few interesting tricks worth knowing. You can ask Siri to perform calculations for you, long-press on results to copy them, long-press the field to paste numbers in, and swipe left or right above the keypad to delete digits one by one. The app can also be used as a scientific calculator with just a simple maneuver.
When it's time to calculate a tip at a restaurant or bar, I usually try some mental math at first, but sometimes I resort to opening the Calculator quickly from the Control Center on my iPhone and doing a quick calculation. But with Apple's Shortcuts app, there's an even easier way, and you don't even have to leave your lock screen to get the results.
If you've running iOS 11.1 through iOS 11.1.2, whether you have an iPhone X or an iPhone 5S, you'll notice that Apple's Calculator app can't keep up with your calculations. That's a because a bug has seriously slowed it down so that operation buttons won't always trigger when you press them. Luckily, there's something you can do about it.