Papers published

How Many Circles Does It Take to ‘Subtend’ an Ellipse Externally? – Cassandra Lee – 3rd issue of Princeton Undergraduate Mathematics Journal

Tuition services:

I have decided to combine my teaching and mathematics engagements on this page.

I am based in Hong Kong, and it is possible to deliver my services over the Internet. I can teach primary and secondary students in Hong Kong in the following subjects:

  • Mathematics (Compulsory+M2)
  • English
  • Chemistry
  • Physics
  • Biology
  • Computer and Information Technology (HKCEE level, Programming module)

Contact me for details and pricing. Students must bring their own textbooks and lesson notes to class.

Current engagements:

Teaching experience:


  • Global Mathematics Project Ambassador
  • Julia Robinson Mathematics Festival (Hong Kong): facilitator
  • Private tutor for Secondary 5 student in HKDSE-level Physics, Chemistry and Mathematics (Compulsory) — intensive
  • Teaching assistant, “Number Theory and Cryptography”, Enrichment Programme for Young Mathematics Talents, CUHK
  • Undergraduate project/seminar in Morse theory
  • Volunteer tutor, Hang Lung Mathematics Tuition Group, Hang Lung Properties Limited (press release)
    • Primary 3 and 4 students
  • Teaching assistant, “Towards Differential Geometry”, Enrichment Programme for Young Mathematics Talents, CUHK (scholarship holder of LET CPSE, i.e. the Learning by Engaging and Teaching Programme, Centre for Promoting Science Education, Faculty of Science, CUHK)
  • Admission test question setter cum grader, Enrichment Programme for Young Mathematics Talents, CUHK
  • Tutor, YMCA (Tuen Mun Branch)
    • After-school Primary 1 (Primary 4 in 1st term, 2015-16) remedial class in Chinese, English, Mathematics and General Studies
    • After-school Secondary 2 Mathematics class
  • Private tutor for several Primary 5 students in Chinese, English, Mathematics and General Studies


  • Tutor, “English Activities for Students of Fresh Fish Traders’ School” Service Programme, Shaw College, The Chinese University of Hong Kong (CUHK)

Programming languages I know:

  • C++
  • Python
  • Dev-Pascal
  • POV-Ray
  • C#
  • MiniZinc

My wish now is to lengthen this list.

I am a blogger and the banner designer of Mathematics blog Mathematics@CUHK »

Mathematical Interests:

Interested parties may contact me to discuss these university-level subjects.


  • Geometry: algebraic, differential, Riemannian, sub-Riemannian
  • Differential equations
  • Linear and abstract algebra

Still learning

  • Analysis: real, complex, functional
  • Computational mathematics: matrix computations and numerical analysis
  • Combinatorics
  • Topology
  • Probability