The number one billion is written as 1,000,000,000 in standard or numeric form. It is regarded as 1 x 10 to the ninth power in scientific notation, where the numeral 9 indicates the number of zeros. It is equivalent to a thousand million: 1,000 x 1,000,000.
A billion used to be written as 1,000,000,000,000 in British English because it was defined as a million million: 1,000,000 x 1,000,000. British English has adopted the American figure of 1,000,000,000 to denote a billion, according to Oxford Dictionaries. The nine zeros in a billion correspond to 9 place values: ones, tens, hundreds, thousands, ten thousands, hundred thousands, millions, ten millions and hundred millions.