Khan Academy: Video explanations of concepts from pre-school through Year 12. Your child can rewatch, slow down, and revisit. Free with no ads if you create a parent account.
nrich.maths.org: Rich problem-solving tasks for all ages. Not about speed or rote—it's about thinking deeply.
Mathspace: Used in many Australian schools. Some free content available; check if your school provides access.
Desmos: Graphing calculator that lets you see algebra visually. Perfect for Year 7-10 students.
PhET simulations: Interactive maths and science activities. Visualise how functions, fractions, and operations work.