You need knowledge and intuition! Choose whether the number that came out is a prime number, or not. If you think it as prime number,push the left green button of "YES". If not, push the right red button of "NO". It is tight not only to mathematical study but little brain training! Requiring special attention, since it will become game over if it does not mistake or does not answer within 5 seconds! If it answers correctly continuously, it will become more difficult and the prime number of a maximum of 3 figures will come out. Since a decoration can be got according to the number of correct answers, You will carry out a complete finger and will do your best! What's Prime Number? A prime number means natural number (positive integer) that is not 1 not to have a positive divisor other than 1 and oneself. (2,3,5,7,...)