Functions and linear models | Pre-algebra | Math | Khan Academy
Work through some of the topics here
Math
Problem of the Week | University of Waterloo - CEMC
Weekly problems, solutions provided a week later
Math Antics | Basic Math Videos and Worksheets
scroll to the bottom for videos on functions - Jack will appreciate these
TikTok Videos
Great math explanations and challenges
MathBitsNotebook - On-Line Study Resources for High School Mathematics
Lesson notes + interactive practice - Jack wasn't a fan...