I did #27 "Introduction to Mathematical Thinking" during Feb-April this year. I enjoyed it a lot and found it challenging without being impossible to complete.

I did #27 "Introduction to Mathematical Thinking" during Feb-April this year. I enjoyed it a lot and found it challenging without being impossible to complete. Finished with a distinction and a feeling of great satisfaction. I'm now doing Coursera's Interaction Design specialisation [1], which is proving to be very informative and a lot of fun. If you're considering doing a MOOC then I'd definitely recommend it. Choose a free, short-ish course to start with, make the commitment, and dive in. [1] https://www.coursera.org/specializations/interaction-design https://www.coursera.org/specializations/interaction-design