Students in 10-12 standards needs any shortcut stratergies and problem solving in trignometry

He has an interesting personality, he's an UPSC Aspirant and works in an organization. He used to teach my nephew Trigonometry and Chess. He teaches and plays chess with his students before starting an individual session. My nephew used to be below average in Maths and now he can solve problems with out any guidance. He has improvised a lot.

This tutor has an unique way of teaching and he helped my brother learn in a quick manner. My brother used to be an average student but his marks has improved a lot. This tutor plays chess with his students to bring more focus and improvise their thinking ability.