Final answer:
The statement: 'And I never need a notebook or briefcase.' best reveals the author's purpose to inform in The Number Devil.
Step-by-step explanation:
The statement from The Number Devil that best reveals the author's purpose to inform is:
"And I never need a notebook or briefcase."
This statement indicates that the number devil is knowledgeable and does not require external tools to share information. It suggests that the author aims to convey math concepts in a straightforward and accessible manner, without the need for cumbersome materials.
By emphasizing the number devil's ability to provide information without the need for a notebook or briefcase, the author highlights the simplicity and practicality of learning about numbers.
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