From the Desmos website
Desmos wants to build a world where every student learns math and loves learning math, where a student’s access to the power and beauty of math doesn't depend on their place of birth, race, ethnicity, gender, or any other aspect of their identity.
Our free suite of math software tools, including the renowned Desmos Graphing Calculator and Scientific Calculator, are used annually by over 40 million teachers and students around the world.
Our cutting-edge technology also powers our free digital classroom activities, thoughtfully designed by teachers for teachers to support and celebrate the different ways students come to know mathematics. These activities are guided by our pedagogical philosophy and open up a world of possibilities for students to explore concepts more deeply, collaborate with their peers on problem-solving, and apply knowledge creatively as mathematicians.
The three parts of Desmos that we want to highlight are (1) Classroom activities on Teacher.Desmos, (2) the Desmos graphing calculator, and (3) Learn Desmos.
To help you get started, here are a few collections of Desmos activities either created for, or well-suited for adult students.