From Marco Santonocito and Antonio Giarrusso, iMathematics is a free phone application for practicing a variety of mathematical subjects, including arithmetic, algebra, geometry, trigonometry, calculus, and probability. As Giarrusso explains, this phone application can be considered "the Duolingo for Learning Math." Like the popular application for learning new languages, iMathematics teaches users new skills in small steps and then quizzes them on new concepts. Students and teachers alike can create a free account; however, some topics and quizzes require purchasing a Pro version. iMathematics is available for iOS or Android devices.