I have a clue how to solve this problem, but I need some extra help. Thanks!

Hi Fredrick,

4.2 x 10^8 =
4.2 x 10

^{8-4}= 2.1 x 10^{4}2 x 10^4 2

I just divided the numbers 4.2 and 2.1 and then I used a law of exponents to subtract the exponents dividing by the same base.

Best of luck,

Shannon