this is what happens at the first start of the school day. the teacher will get a piece of paper (or just use their memory if they are a smart teacher) that has the names of the kids in the class on it. she (or he) will read out the names on the list to see who is present, and who is absent.
often the class clown will make a silly answer to make the class laugh at the pure hilarity.
"Ok, let's just get the roll call out of the way and we can get stuck into our work!"
"Is Leah here?"
"Is Dean here?"
"Oh, you kids, you really crack me up, I swear, this is why I got into teaching."
*collective lack of interest*