Here is the online challenge ready to rub the brain cells of yours.
We brought you a challenge that involves a math riddle similar to those you used to solve in middle school
Here is the solution and procedure to get the correct answer
The correct answer is 3.
Between 18 and 10, the difference is 8.
Between 10 and 6, the difference is 4.
Between 6 and 4, the difference is 2.
Similarly, the difference between 4 and 3 is 1, hence 3 is the correct answer