Full marks always

A teacher was the envy of the whole school as the Middle School students always got full marks whenever the principal visited that particular class and checked on their knowledge. Whenever the teacher was asked to put questions to the students, they all raised their hands up, and all the time they would get the right answer. Nobody could find out the secret of his extraordinary success. All the other teachers at times were becoming jealous of him. When this teacher finally retired, someone asked him the secret of his achievement and the brilliance of his students. His answer left everyone dumbfounded. ‘Well, whenever the principal would come to my class, I would always tell the students a very simple formula. If they knew the answer to my question, they would raise their right hand. If they didn’t know the answer, they would raise their left hand. And so I would always pick the children with the right hand raised up! And our inspector always was impressed. But I insisted that the students study as hard as they can anyway.’