What is abbreviation of billion?

Answer 1

It seems that it is simply "B", even if some media use "bn"

If you look at the pattern. k means thousand; this comes from the SI prefix kilo: which means 1000 and is abbreviated with k. M means millions because the SI prefix for millions, Mega, is abbreviate M. The SI prefix for billion is Giga (abbreviated G) so I use G for billions

In accounting, M is used for thousand from the roman numeral for Thousands. MM is used for a million which is one thousand squared. continuing on this pattern, MMM could be used for a billion which is a thousand cubed.