Answer:
4 bilion = 4 × 10⁹
Step-by-step explanation:
The scientific notation:
[tex]a\cdot10^k[/tex]
where
[tex]1\leq a<10,\ k\in\mathbb{Z}[/tex]
4 billion:
in USA: 4,000,000,000
in Europe: 4 000 000 000 000
[tex]4\underbrace{000000000}_9=4\cdot10^9[/tex]
