-
InfluxDB
Power Real-Time Data Analytics at Scale. Get real-time insights from all types of time series data with InfluxDB. Ingest, query, and analyze billions of data points in real-time with unbounded cardinality.
It's probably copyright violation to copy their exercise sets (depends on the license and where they got them). There are existing maths quiz grading systems that could be used for similar purposes (based on your description; I haven't done that Udacity course), and I'd recommend STACK [1], a Moodle [2] plugin. Both are open source.
[1] https://stack-assessment.org/
[2] https://moodle.org/
NOTE:
The number of mentions on this list indicates mentions on common posts plus user suggested alternatives.
Hence, a higher number means a more popular project.