What is this number - 3000000000000?

Answer 1

3000000000000 = 3 x 10^12;

* In countries that use the long scale (based on powers of a million) like Europe:

3 x 10^12 = 3 x (10^6)^2 = 3 billion (the million to the power 2 implies bi-);

* In countries that use the short scale (based on powers of a thousand plus one) like USA:

3 x 10^12 = 3 x (10^3)^(3+1) = 3 trillion (the thousand to the power 3 + 1 implies tri-).