Pupil-1:  Our teacher talks to herself does yours?

 Pupil-2:  Yes, but he doesn't realize it, he thinks we're actually listening!

 Pupil-1: I failed every subject except for algebra.

Pupil-2: How did you keep from failing that?

I didn't take algebra! 

Teacher: Are you good at math?

Pupil: Yes and no

Teacher: What do you mean?

Pupil: Yes, I'm no good at math!

Teacher: If 1+1=2 and 2+2=4, what is 4+4?

Pupil: That's not fair you answer the easy ones and

 leave us with the hard one!

Teacher: Now class, whatever I ask, I want you to all

answer at once.

How much is six plus 4?

Class: At once!