Arnaldo stated that a billion is the same as a million million. Professor Piraldo corrected him and correctly said that a billion is the same as a thousand million. What is the difference between the correct value of a billion and Arnaldo's statement?
(a) 1000
(b) 999000
(c) 1000000
(d) 999000000
(e) 999000000000
The correct option is (e).

Arnaldo said that 1 billion $=1000000 \times 1000000=1000000000000=10^{12}$. Professor Piraldo corrected him, saying that 1 billion $=1000 \times 1000000=1000000000=$ $10^{9}$. The difference is

$$
1000000000000-1000000000=999000000000
$$