And I got back this bad answer:

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Would you tell me what an irrational number is? Is it a number that cannot be written as a fraction, like pi or e? Or is it something else?

Okay, I see. Thanks for clarifying that.

Then what is an irrational number? It is a number that cannot be written as a fraction, correct?

Okay, I understand. Then what is a number that can be written as a fraction? It must be a rational number, right?

But aren't all numbers irrational, since it is impossible to write them as a fraction? And any rational number must be irrational, right?

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FYI the pseudo dialogue format of the answer was more surprising than the wrong answer