Mma Ramotswe raised a hand. “Stop, Mma Makutsi. You cannot say that. You are not a stupid woman. Would a stupid woman have got ninety-seven per cent? Would she?”

Mma Makutsi looked doubtful. Mma Ramotswe was right about ninety-seven per cent: it was not the mark of a stupid woman. “Well, I was thoughtless on that occasion—put it that way, Mma. I just didn’t think.”

“Anybody can forget something, Mma,” said Mma Ramotswe. “We are human, after all.”

That, thought Mma Makutsi, was true. We were all human, even Mma Ramotswe herself, who was so kind and understanding and so quick with her forgiveness; even Mma Ramotswe could forget things and make mistakes. Her marriage to Note Mokoti had been a mistake, a big mistake, and there was that time she hit the tree when she was trying to park her tiny white van, and the occasion when she had put the wrong piece of paper in an envelope and sent a letter intended for person A to person B. That had been an unfortunate mistake, as in the letter to person A she had said that she thought it was person B who was stealing from the petty cash in person A’s office; very unfortunate, but very effective, as person B, alarmed at the discovery of his misdeeds, had immediately run away. That had sorted out the problem, but it was a mistake nonetheless.

Remembering the mistakes, Mma Makutsi smiled.

“Why are you smiling?” asked Mma Ramotswe. “Do you not agree with what I said about mistakes?”

“Oh, I do agree,” said Mma Makutsi. “I agree with you, Mma. It’s just that I was thinking about…” She hesitated for a moment before continuing, “I was thinking about your mistakes.”

Mma Ramotswe was not offended. “I have made many of those,” she said. “I have made some very bad mistakes. I cannot hide that fact.”

“Do you remember that letter?” asked Mma Makutsi. “The one in which you said—”

Mma Ramotswe sank her head in her hands. “Oh no, Mma! Please do not remind me of that. I feel all hot and bothered when anybody reminds me of that.”

“But it had a good result anyway,” said Mma Makutsi.

Mma Ramotswe nodded. “Yes, sometimes mistakes can be a good thing. You might be in town and you mean to go into one shop and you go into another. And then you find a very old friend in that other shop. Or you meet the person you’re going to marry—something like that.”