Nika found mathigon--textbook-of-the-future:

• Moderately builds student knowledge“It helps me in soving some math tasks.”
• Significantly improves teaching efficiency and productivity“Students implement stuff they learn on this site in solving tasks in class.”
• Slightly saves school money
• Slightly provides school data
• Significantly teach-problem-solvings
• Slightly improves creativity and critical thinking“Not really”
• Moderately improves creativity and critical thinking“Not really”
• Slightly improves parent engagement