Mike   : Hey, Min-su! Let me show you something.

Min-su : OK.    ⓐ   

Mike   : Write down three numbers ⓑ연속해서.

Min-su : Go ahead. I’m ready.

Mike   : Write down the same three numbers backwards. Subtract the smaller number   ⓒ  the bigger number.

Min-su : OK. I did.

Mike   : The answer is 198.

Min-su : Wow. ⓓ참으로 놀랍구나! How did you know?

Mike   : It’s a secret.