"Facilities."
The woman looked toward him.
"Yes?"
"You're blocking the aisle."
"Sorry."
She moved the cart two feet.
But her eyes returned to the board.
The Professor watched her for another moment.
Then smiled.
Not pleasantly.
"Do you recognize any of it?"
A few people laughed before realizing he was serious.
The Black woman looked at the equation.
Then at him.
"Some."
That produced louder laughter.
The Professor glanced toward the audience.
"There you have it."
He walked toward the chalkboard.
"Three hundred mathematics students spend an entire weekend suffering, but our custodial department apparently finds it familiar."
The young woman did not smile.
One student near the aisle stopped laughing.
The Professor continued.
"Perhaps you'd like to try?"
The hall became quiet.
The Black woman looked at him.
"Are you asking seriously?"
He spread one hand toward the board.
"Fifty thousand dollars."
Several phones rose.
Students were recording now.
The Professor noticed and enjoyed it.
"Any student."
He looked deliberately at her badge.
Then added:
"Assuming, of course, you're actually enrolled."
She reached into the back pocket of her work trousers.
Pulled out her phone.
Opened the student portal.
Held it toward him.
He barely looked.
"Mathematics?"
"Applied mathematics."
This changed the room.
Not enough.
But some laughter disappeared.
The Professor nodded slowly.
"Undergraduate?"
"Senior."
"Interesting."
He glanced at her mop.
"Night program?"
"No."
"Then why are you dressed like that?"
The question landed differently.
The woman lowered her phone.
"I work."
"Clearly."
Silence.
She looked at him.
He smiled.