Answer:
2 x 10^11 and 4 x 10^11
Step-by-step explanation:
We use scientific notation because it makes it easy to calculate things on very large and very small scales.
1 billion = 10^9
So 200 billion = 200 x 10^9
But we want that starting number to be between 1 and 10.
200 x 10^9 = 2 x 100 x 10^9 = 2 x 10^2 x 10^9 = 2 x 10^11
400 billion has the same number of zeros as 200 billion sooo
400 billion = 4 x 10^11
