KUALA LUMPUR, April 13 — The Singapore “Primary 5” mathematics question that had gone viral on Facebook is in fact a question from a mathematics competition for Secondary 3 students, the Straits Times reported.

The Singapore English daily quoted Henry Ong, founder of Singapore and Asian Schools Math Olympiads that organised the competition as saying the question was one from the April 8 Math Olympiad.

Ong also expressed surprise that a screenshot of the question could be circulated online despite students not being allowed to have mobile phones with them during the competition.

Earlier Malay Mail Online reported that the question had left many adults baffled and arguing online over its solution because they were apparently stumped by a seemingly simple primary school math question.