[stylist] Writing question

[Robert Newman]

When in a narrative of a story and you are needing to speak of a number,
under what circumstances do you use an actual numeral/number verses writing
out the word? For example- the house is 100 years old. Or- She carried the
two little dogs up to the seventeenth floor. 

Are there rules? Or is it just style?


Robert Leslie Newman 
Email- newmanrl at cox.net
THOUGHT PROVOKER Website- 
Http://www.thoughtprovoker.info