Teacher: What happened in 1809?
Student: Abraham Lincoln was born.
Teacher: What happened in 1819?
Student: abraham Lincoln was ten years old.
Teacher: How old is your dad?
Student: He is as old as I am.
Teacher: How is it possible?
Student: because he became a dad only after I was born
The student has simply answered every of the teacher's questions correctly....I'm sure even the teachers know that!