How to write 1 billion numerically in the US?

I know the British write the amount (and consider the amount differently than the US does) – 1 billion is a 1 with how many zeros after it.

Popular: Does the word "lunch" have the same meaning in American English?!? Use of the possessive apostrophe in "its"? I need help on my Personal Law School Statement? Mandatory military service in my country, when applying for grad school, fall or spring admission? Please help, I don't know what to do?
More: Should I apply to both UCLA and USC? I need help.? Is this a good ACT score? I need a quote from Of Mice And Men that shows how people during the great depression adopted a false sense of security.? Whats wrong with me? HELP !?