The Frustrated Teacher
The fifth-grade math teacher wasn’t in the mood to give his planned lesson.
The class was in a restless mood and he just didn’t have the energy to to teach the prepared material and enforce discipline.
He decided to give himself a break by giving the class an exercise that would take up the entire scheduled hour, but would only take him a minute to assign and explain.
The problem he devised was simple – the students were to add every whole number from 1 thru 100.
About five minutes later, the teacher was sitting at his desk, mentally patting himself on the back for his ingenuity. Most of the students were sitting at their desks, deep in thought. A couple of the slower writers were still writing numbers on their papers.
One of the brighter boys raised his hand.
The teacher frowned in mild annoyance at the interruption of his “free” period.
“Yes?” he called on the student “do you need help?”
“No,” replied the student, “I finished, and the answer is …..”.
The teacher was shocked. “How did you add up all the numbers so quickly?”
The student expalined the simple but brilliant method he had used.
The teacher groaned to himself as he got up and walked to the blackboard.
He now had fifty minutes of class to teach.
1) What was the answer?
2) What was the student’s “trick”?
(I am sure this is an oldie, since I remember it from an SRA. If you already know the answer, “chap nischt”. If you know what an SRA was, you too may be an oldie:))