One billion is a very large number especially if you are counting money, years or people. When written numerically there are nine zeroes in the number one billion. 1,000,000,000.
http://answers.ask.com/Science/Other/how_many_zero...

There are 9 zeros in 1 billion
http://wiki.answers.com/Q/Who_many_zeros_are_in_1_...

In the U.S. 1 followed by 9 zeros, and in Great Britain 1 followed
http://www.chacha.com/question/howmanyzerosare...

it's 1,000,000,000,000 so there are 12 zeros and 1 trillion equals to 1,000 billion
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