The puzzle that makes 99% of people good at math answer wrong

This is a math puzzle with 3 rows of X's: 4, 6, 12,1, 1 and 1, 9, 15, 2, 1 and 4, 9, ?, 2, 2. This problem requires you to find the rule to guess which digit is placed after the question mark between the numbers 4, 9 and 2, 2.

This is an extremely difficult puzzle. If you want to find the answer, take a pen and paper and calculate as carefully as possible.

99% of people get this quiz wrong.

If you find the most correct answer, scroll down to the comments section to write down your most correct answer and see how many people think the same as you.

Khanh Son

Source: https://vtcnews.vn/cau-do-khien-99-nguoi-gioi-toan-tra-loi-sai-ar907970.html