To start, you have:

4.8 x 10^8

/6 x 10^3

You can cancel out 10^3 from top and bottom, which leaves you with

4.8 x 10^5

/6

Now divide 4.8 by 6 = .8

So, you are left with .8 x 10^5

This is better expressed as 8 x 10^4.

To start, you have:

4.8 x 10^8

/6 x 10^3

You can cancel out 10^3 from top and bottom, which leaves you with

4.8 x 10^5

/6

Now divide 4.8 by 6 = .8

So, you are left with .8 x 10^5

This is better expressed as 8 x 10^4.