I never heard of Desmos until now; it looks like an outstanding educational tool with pages and pages of exercises, demos, and aids for teaching math. But I ca

I never heard of Desmos until now; it looks like an outstanding educational tool with pages and pages of exercises, demos, and aids for teaching math. But I can't fathom how they make money. Their "about" page lists 29 high-qualification employees, and they're located in a high-cost city (San Francisco). If the loaded cost of each employee is $150K, they'd have to make $4.3 million a year just to pay salaries and overhead. I can't find a single item on their website that has a price listed: everything is free! They don't even have ads. They talk about partnerships and such, but I can't figure out how they charge money and what they charge for. Public schools are stingy when it comes to learning aids; teaching math is not in the same category like spending for a football stadium. There are 56 million elementary, middle, and high schools in the U.S.[1]. If they charged $1 per student in some partnership deal, they have to sign up at least 7% of the entire U.S. student body just to meet payroll and overhead. Don't get me wrong, their software looks absolutely wonderful, but I don't understand the business case. [1] https://nces.ed.gov/fastfacts/display.asp?id=372#PK12_enrollment https://nces.ed.gov/fastfacts/display.asp?id=372#PK12_enroll...