This puzzle has gone viral on social media sites, and it has stumped many:
— Mr. Russell’s Class (@MrRussellsClass) October 13, 2014
The blog Centauro says the puzzle is used in Hong Kong, and it appears on tests for children entering the first grade.
“This was one of the questions that children of the age of 6 faced as part of their entry exam to a primary school in Hong Kong, since this was published on the Chinese social media network Sina Weibo (Chinese twitter), it has been touted as one of the most popular things to come out of China since the invention of fireworks,” it says.
Students have less than 20 seconds to solve it.
You can find the answer below.
Answer: The trick with the puzzle is to flip the image upside down, therefore the answer is 87.