Today is the first time in a decade that I actually wished I was back in school. Mathpix is an iOS app that can recognize and answer handwritten math equations in seconds. Open the app, point the camera toward your math problem (you'll need legible handwriting, or it won't work properly), and it'll give you the correct answer along with step-by-step directions to reach the solution. Mathpix even works with more complex equations that require graphs or charts.
The app works by sending the equation to a server, so you'll need a connection to use it. Usually a math app that can solve problems wouldn't be allowed in schools, but Mathpix is essentially a far better version of the now very old TI-84 graphing calculator, and a lot cheaper (it's free). You can download Mathpix on iOS today.