"one hundred" and "a hundred" 100

H   Thu Jun 25, 2009 1:05 am GMT
When is "one hundred" used and when do we say "a hundred"?
100   Thu Jun 25, 2009 1:46 am GMT
"One hundred" is used when writing checks, and perhaps in other formal situations. "A hundred" if often used otherwise.

"This the biggest flood in a hundred years."

"Given that the US Senate has exactly one hundred members, percentages are easy to calculate."