By Becky Lo

A poster in the room at Goldhill Centre reads: "Miss Loi's temple, enter and be saved."

Joss Sticks is the name of Ms Celine Loi's tuition centre, where at least 20 students walk in every weekend to work on their maths.

The full-time tutor of eight years has about 80 students under her charge now, each paying $60 a lesson.

The maths guru earns a five-figure monthly income from tutoring.

News of her centre spread by word of mouth and also through her website (www.exampapers.com.sg).

The interactive webpage of the 33-year-old, who is single, is laced with humour.

For example, students can avail themselves of her services for the "effective prevention of last-minute Buddha foot-hugging syndrome", a Chinese idiom for last-minute exam cramming.

Ms Loi also sells exam papers at about $60 a subject on her site.

The maths graduate from the National University of Singapore has at least 10 students on her waiting list now.

She also has no qualms in "sacking" any student.

"I tell those who refuse to work hard and do not need tuition not to come back," she said.

Her "favourite" ones are those with an F9 grade.

Every year, a month before the final exams, Ms Loi gets SOS messages from at least 10 such students.

"I had students who scored less than 10 marks for their preliminary exams and ended up with an A in the O-level exams," she said.

Ms Loi typically has a 3 to 10pm workday. On school holidays and weekends, she works from 8am to 10pm.

But when the exams draw nearer, she works past 11pm at times.

"Sometimes, I get gastric pains because I don't have time for meals," she said. "I also don't have much personal time."

This article was first published in The Straits Times on 15 June 2008.