Multiplication made easy

One day a mathematics teacher was giving each of his students a very difficult problem to solve. He was asking them about fractions, square roots, the circumference of a circle and so on. Naturally, most of the students could not solve the problems.

The teacher asked one boy, "Please tell me what is 7,000 divided by 1/7?"

The boy tried and tried, but could not solve the problem. Then a brilliant girl said, "That is just 7,000 times 7 or 49,000."

The teacher was very, very pleased and said, "Yes! That is wonderful." Then the teacher said to a boy who was very clever, "I shall give you a complicated multiplication. Will you be able to do it?"

This student said, "No matter how complicated your multiplication problem is, I will definitely be able to do it."

The teacher said, "That is fine. How long do you think you will take?"

"It will take me no more than a fleeting minute," the student replied.

The teacher was surprised. "What are you saying?" he asked.

"Will you be able to multiply any numbers so quickly? How is that possible? Even I will take some time to multiply together two long numbers."

"I tell you, I can do it faster than the fastest!" said the student.

"Very well," said the teacher. "Then let me see you do it." Then he gave the student a very difficult multiplication problem. Both numbers were seven digits long.

The boy immediately got out his calculator and multiplied the two numbers very quickly. The teacher asked, "What are you doing?"

The boy said, "I am multiplying! You did not tell me that I could not use a calculator!"