Why did Arjun listen for twenty minutes instead of hanging up?

The first time the old man called, Arjun said, "Sorry, wrong number," and hung up. The second time, the next evening, the same tired voice asked for "Shyam", and Arjun explained that there was no Shyam at this number.

"Ah," said the voice. "Shyam was my son. This used to be his number. He moved to Canada and changed it. I forget sometimes."

Arjun did not know what to say, so he asked how the old man was. The old man, whose name was Mr Iyer, said he was well, and then talked for twenty minutes about his garden, his knees and the price of vegetables. Arjun, who was supposed to be studying for his accountancy exam, listened.

After that, Mr Iyer called every few days. He always began by apologising for the wrong number, and Arjun always said it was all right. He learnt that Mr Iyer had been a teacher of mathematics for thirty-five years, and when Arjun mentioned a sum he was stuck on, Mr Iyer solved it on the phone in four minutes, faster than the textbook.

In March, Arjun passed his exam. He called the number he now knew by heart to tell Mr Iyer.

A woman answered. She was Mr Iyer's daughter-in-law, visiting from Canada. "He talks about you," she said. "He calls you his wrong number. He says it is the best number he has."