If the numbers go from 10 all the way down to 1 then you've got a first edition.

If it goes from 10 to 2 then you've got a second edition and so on.

Unfortunately these aren't worth as much.

There are three types of binding:

• Laminated pictorial boards (not bound in cloth - shiny-ish cover) - only 500 of these printed so very valuable
• Cloth bound with JK's signature in gold on the front - there are 1000s of these because they were published later when publishers knew it would success
• Paperback - millions published so not really worth so much.

So how much money can you make?

• Philosopher's Stone first edition They are very rare - only 500 were printed
  Unsigned they can be worth £3,000 to £4,000
  Signed £8,000 to £10,000!

• Chamber of Secrets first edition
  Unsigned they can be worth £400 - £600.
  Signed £1500

• Goblet of Fire
  First editions aren't worth that much because there were so many printed!

• Deluxe Editions A complete collection of all four books in the series as first editions of the deluxe editions can be worth £1000.
  If signed £2000 - £3000.

If you have any of these and the condition is good, get in touch with a well-known auctioneers like Sotheby's or Christie's.

Ask to speak to a children's book expert.