An intelligence test, which involves adding up a sequence of numbers, is sweeping the internet - and leaving users dumbfounded in the process.
The test asks users to 'think outside the box' by working out two different but correct answers to a series of equations.
Makers write: 'Firstly, think outside the box! This maths riddle is not that simple. Even though there’s usually one right answer for maths problems, two common solutions are causing heated debates all over the world.'
The makers say that only one in 1,000 people can figure out the second possible answer to the test, so can you?
The makers explain that most people will begin by adding 1 + 4 to reach the answer 5.
Then they'll add 2 + 5 to the sum of 5 to get an answer of 12.
The majority of users will use the same process in the next line, adding 3 + 6 to get 9, then add nine to the sum in the equation above (12) to reach the figure 21.
In the last stage, they will add 8 + 11 to get 19, before adding it to the sum of the previous line (21) to get 40.
While makers say that 40 is a widely accepted and correct answer, there's another answer - and only a select few will reach it.
While makers say that, of course, 1 + 4 = 5, intelligent people will get the answer by adding 1 to 4 x 1.
Using that formula, they'll add 2 to 2 x 5 to get 12.
They'll then add 3 to 6 x 3 to get 21.
And to reach the final and alternate answer, they'll add 8 to 11 x 8 to get 96.