10/99 of my Xbox friends list are playing it. There's 45m Xbox live users...
So... 45,000,000/99 = 454,545
454,545 x 10 = 4,545,450
There's 4,545,450 people playing Black Ops 2 on Xbox Live right now.
My prediction threads:
Wii U will sell under 40m units (made on 14th September 2012)
PS Vita will sell under 20m units (made on 30th September 2012)
Wii U will sell under 7m in 2013 - I was right