Question :
This tricky math problem went viral a few years back after it appeared on an entrance exam in Hong Kong for six-year-olds. Supposedly the students had just 20 seconds to solve the problem!
Solution :
Answer is 87.
This is not a maths question, its just a tricky question. If you flip the image upside down, you will see that it is a simple number sequence from 86 to 91.