Behind him are white chalk letters filled with mathematical formulas.

The next second,

The man woke up from his coma and immediately started shouting.

"Someone come! Help!!"

The voice was hoarse, making people feel a sense of terror and despair.

At this moment,

The camera changed to shooting from the perspective of broken glasses, and vaguely, the door of this classroom was pushed open.

"woke up?"

I couldn't see the man's face clearly, but it was easy to tell from his voice that he was not very old.

"Inside the box is your mobile phone. You can use it to call the police or an ambulance, provided you get the password for the box."

"The password is the sum of the answers to all the exercises in this exercise book... and then the square root."

The next second,

The masked man kept hammering the middle-aged man on the head, and stabbed the middle-aged man's arm with a pen. Blood immediately flowed out and could not be stopped at all.

"It took me five hours to calculate it. As a teacher, you should be faster than me. Two hours is enough."

"Take good care of your "ink"."

The masked man pointed to his bleeding arm, turned and left.

for a moment,
Chapter completed!