"No."
"What if we get ninety-nine percent?"
"You receive one hundred percent of nothing."
The room erupted.
The Professor smiled.
Then added:
"Mathematics is cruel that way."
At the rear of the lecture hall, a side door opened.
Almost no one noticed.
A young Black American woman stepped quietly inside carrying a mop.
She was twenty-two.
Slim.
Warm brown skin.
Large dark eyes.
Her hair was braided close to the scalp before falling into a neat low braid behind her shoulder.
She wore the light-blue polo shirt issued by Halston Facilities, dark work trousers, white sneakers, and a laminated temporary-access badge clipped near her collar.
A cleaning bucket rolled behind her.
She paused when she saw the room packed.
The schedule taped to her cart said Lecture Hall One should have been empty until ten.
It was not.
The Professor noticed her before anyone else did.
His expression changed.
Not dramatically.
Just enough.
"What is this?"
The Black woman looked toward him.
"Facilities."
"I can see the uniform."
A few students turned around.
She kept one hand on the mop.
"The hall was scheduled for cleaning."
"After class."
"The system says before ten."
The Professor checked his watch theatrically.
"It is nine-thirty-seven."
"Yes."
"So now would be during class."
She glanced toward the packed seats.
"Looks that way."
A few students laughed.
The Professor did not.
"You can come back."
She nodded.
"All right."
She began turning the cart.
Then stopped.
Her eyes had moved toward the board.
The Professor noticed.
So did several students.
She stared.
Not casually.
Not with confusion.
Her expression sharpened.
Her head tilted slightly.
She read from the top line downward.
Then again.
The Professor folded his arms.
"Problem?"
She did not answer immediately.
One graduate student whispered something to his friend.
The Professor raised his voice.