One of the topics he tutored was geometry and Mark, although only five years old, became fascinated by what his father was teaching and he persuaded his father to teach him some geometry.
Isa ng ang paksa siya tutored ay geometry at Mark, kahit lamang ang limang taong gulang, naging nabighani sa pamamagitan ng kung ano ang kanyang ama ay pagtuturo at siya hikayat ng kanyang ama upang magturo sa kanya ng ilang geometry.