Intellectual questions seem easy but are surprisingly difficult

Using your intelligence and mathematical reasoning, give the correct result behind the question mark.

The question seems very simple but many players fail because of their impatience. So you should be calm to avoid making the same mistake as them.

Can you give the correct answer to this question?

Quickly register yourself in the top smartest people by leaving your answer in the comment box!

Trung Temple

Source: https://vtc.vn/cau-hoi-tri-tue-tuong-de-ma-kho-khong-tuong-ar833721.html