Answer:
See below
Explanation:
The smallest amount is 4.2*10^5 which is 420,000. You count 5 places from the end to get the power. The number must be something between 1 and 10 to qualify as being scientific notation.
The second smallest number is 3.8 million or 3,800,000
The largest number is 3.9 million or 3,900,000