Prediction: Your result will be 18
 Think of a number.
 Add 7 to it.
 Subtract 2.
 Subtract your original number.
 Multiply by 4.
 Subtract 2.

Explanation:
This problem gives the illusion of guessing an unknown number, but the unknown has been cancelled
mathematically.
( X + 7  2  X ) × 4  2 = 18
© Copyright  Antonio Zamora