How many children does Bob Cratchit have in A Christmas Carol?

Bob Cratchit and his wife have six children.  The eldest is Martha, who is old enough to have a job as an apprentice to a milliner.  She comes home late from work for Christmas dinner and her mother frets about the time.  The second oldest daughter is Belinda.  The oldest son is Peter.  He is also older, as his father discusses him getting a job in the near future.  Martha, Belinda, and Peter are all helpful in assisting with the preparation and serving of the special meal.  There are two younger children, a boy and a girl, whose names are not mentioned.  They are playful and they beg Martha to hide before their father gets home.  Last there is Tiny Tim, who is crippled.  He is well behaved and has a cheerful attitude.