A local Primary school was visited by the Government School Inspector who was there to check that teachers were performing well in their respective classes.
She was very impressed with one particular teacher. The Inspector noticed that each time the class teacher asked a question, every child in the class put up their hands enthusiastically to answer it. More surprisingly, whilst the teacher chose a different child to answer the questions each time, the answers were always correct.
The inspector was accompanied by the school Principal, who got struck by surprise. Because he knew that the class has average students whom he sure would not know the answers for all the questions.
But how did they answer every time? The puzzle Principal asked the teacher and got stunned by his smart thinking.
The children were instructed to ALL raise their hands whenever a question was asked. It did not matter whether they knew the answer or not.
If they did not know the answer, however, they would raise their LEFT hand.
If they knew the answer, they would raise their RIGHT hand.
The class teacher would choose a different child each time, but always the ones who had their RIGHT hand raised.