Test your knowledge of math with the below problem, which was purportedly created to challenge third graders at a Vietnamese school.
If you fail the challenge, scroll down for a tentative answer.
The problem requires nothing other than your skills in addition, subtraction, multiplication and division, but it has left many people, including parents, teachers and those with a doctorate degree, scratching their head, according to newswire VnExpress.
The Hanoi-based news website said it received the question from a reader from the Central Highlands province of Lam Dong, whose nephew could not solve it.
The third grader was working out a set of problems provided by his school to prepare for the final examination when he found the conundrum, according to the reader, Ho Huu Cong.
“He consulted me but I too failed to solve it,” Cong wrote. “Is such a tough math problem appropriate for third graders?”
Tran Phuong, deputy director of a Hanoi-based talent support center, said in terms of knowledge level, the problem is suitable for third graders, who have already learned the order of operations.
But to find the answer to it is a different story, he told VnExpress.
“The problem is a tough one even to those who are good at math, and is a real challenge for third graders and those in the mountainous areas,” he said.
The teacher asserted that there are 362,880 possibilities to fill in the blanks, but only a few correct solutions.
“Even an adult must try many times before they can find the answer,” he said.
“I have sent the problem to many people, including some having a doctorate in economics, but they are still solving it.”
Nguyen Ngoc Giang, who is doing her Ph.D. at the Vietnam Institute of Education Sciences, said she used programming language to find the solution, and what she got was “74 sheets of A4-paper full of correct answers.”
But it is not that easy if you have to use your brain, she said.