A PUZZLING question that tests upper secondary students' logical thinking skills in a mathematics contest here has taken the world by storm.
Several newspapers and websites around the world - from Britain and Malaysia to Canada and the United States - picked up the maths question and asked their readers to solve it.
The question, which had a photograph, was shared more than 4,500 times. The question gives 10 dates and asks students to figure out the birthday of a girl named Cheryl using limited information.
Some netizens had issues with the way the question was phrased and criticised the English used, while others made comments about Cheryl's coy behaviour.
The question was first posted by TV talk show presenter Kenneth Kong last Saturday. It stumped many netizens and prompted a rush of attempts online to try and tackle it.
The Singapore and Asian Schools Math Olympiads (SASMO), which set the question as part of its yearly contest, clarified on Monday that it was for Secondary 3 and 4 students.
Mr Kong had said he obtained the question from a friend whose Primary 5 niece had it as homework from her school.
British newspaper The Guardian said the question shows why Singapore comes out tops in international rankings in maths.
In the latest Programme for International Student Assessment, held in 2012, Singapore students came in second in maths, behind their peers in Shanghai.
Educators and publishers abroad now pay close attention to how maths is taught in Singapore - dubbed Singapore maths.
But the baffling question is not the toughest in maths contests here. Mr Henry Ong, founder of SASMO, said the contest, first held in 2006, was formed to give students a chance to try questions that are more manageable.
SASMO is meant for the top 40 per cent of primary and secondary schoolchildren. More than 28,000 contestants last week took part in the competition for primary and secondary schoolchildren. About 5,000 were from Singapore.
"The question highlighted was one of the top two most difficult questions in the test, but it would still be considered easy in the other competitions," he said, referring to contests held by the Singapore Mathematical Society (SMS).
An estate manager who took part in Olympiads in school said contests held by Raffles Institution, Hwa Chong Institution and the SMS are actually harder. Singapore is very well-regarded in the competitive maths scene, globally, he added.
Associate Professor Victor Tan, SMS' vice-president, said about half of the questions in a typical contest are "more challenging" than the regular maths curriculum, in order to sift out the best students.
A team of six is then chosen to represent Singapore at the International Mathematical Olympiad.