The participants who remain in their seats are to put their heads on the table/desk with their eyes closed and keep one thumb up.
Each in turn names the person they think pressed their thumb or tapped their head.
To make the game fair, the teacher can alternate the order in which the participants are called each time (such as from the front of the classroom to back, or left to right, or some other pattern).
[5] The origin of this elementary school game being played in American classrooms goes back to at least the 1950s, perhaps earlier.
[6] Squid Game: The Challenge did an alternative version of Heads Up Seven Up, in episode 9 "Circle of Trust".