SINGAPORE - A "Primary 5" mathematics question that went viral on Facebook and had many people cracking their heads is in fact a question from a mathematics competition for Secondary 3 students.
It was one of the questions students who took part in the Math Olympiad on April 8 had to answer, said Mr Henry Ong, founder of Singapore and Asian Schools Math Olympiads which organised the competition.
Mr Ong said he was surprised to find the screenshot photograph of the question being circulated online. He told The Straits Times: "We were very surprised because students were not allowed to keep their mobile phones on them."
He said that in his 10 years of organising such competitions for students in the Primary 2 level up to the Secondary 4 level, questions have never been leaked.
Students from more than 30 secondary schools here took part in the competition which was held on April 8 this year. Students were either selected by their teachers or volunteered for the competition.
The questions were set by a team of mathematics experts, including professors here and overseas.
The same set of questions was also given to participants in 14 other countries, including Britain, Malaysia, Brunei and Uzbekistan. Mr Ong said that Cambodia has yet to run the competition, and will do so on May 4. The leaked question will be replaced.
He said that leaking the question is considered cheating, and the student who took and circulated the photo can be disqualified from the competition.
The Ministry of Education told The Straits Times the question was not meant for Primary 5 pupils, who are around the age of 11.
"This question is not part of the Singapore primary or secondary mathematics syllabus," it said. "It is not reflective of the type of questions that are set in our mathematics assessments."
Parents and tutors agreed that the question did not test primary school maths concepts.
Mr Michael Tan, 46, a church worker who has a son in Primary 5, said: "It's fine if schools use them for fun and to challenge students, but these sort of questions should not be in exams."
Mr Tan Weiqiang, director of Junior Wonders Tuition Centre, said some schools may want to "stretch their brightest students" with such questions, but it is "very uncommon".
"This isn't what mainstream school students should be worrying about," said the former primary school maths teacher.
Mr Wallace Wong, a maths tutor and co-founder of tuition centre Study Room, said: "This isn't an examinable question but it could have been used to get kids thinking and interested in the subject. Sometimes, we provide puzzles like these for our students, to help them think out of the box, instead of the usual multiplication, division, fraction concepts."
Mr Zhou Shicai, who runs NickleBee Tutors, said: "It tests the child's comprehension and critical thinking skills, and his ability to apply logical thinking to an unfamiliar problem."
And if you are wondering, the answer to the question is: July 16.