Those who stayed up waiting for their Pottermore email probably remember the challenges they faced in unlocking their account. Now the site, according to the Pottermore Insider, is at it again.

There is now even more to discover on Pottermore. Selected Moments in Harry Potter and the Philosopher’s Stone now contain excerpts from the digital audio book for you to enjoy.

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If you haven’t discovered where these audio book excerpts are yet, the Insider is on hand to help you locate the chapters or Moments in which they can be found. Over the next five days, we will be releasing different puzzles that will lead you to each of the audio book excerpts in turn.

Are you prepared for the first puzzle? Get ready to add it up…

Using information from the story, complete the following sum to find the chapter in Book One on Pottermore in which an audio book snippet appears:

The number of minutes Professor Lockhart gives his class to complete a test in their first lesson with him, minus the amount of players on a Quidditch pitch, plus the amount of inches of James Potter’s wand, minus the amount of bedrooms in the Dursleys’ house, minus the amount of Galleons a single unicorn horn costs, plus the number of streets away that Mrs Figg lives from the Dursleys.

Whew! I know I definitely can’t think of the answer to that one off the top of my head! Are there any hard-core fans who can?