18. Marianna wants to run at least 6.2 miles to train for a quarter-marathon. The inequality
m> 6.2, where m is the number of miles she
has run, represents the runs where she met
her goal. Represent the solutions of the
inequality on the number line.

You have to round it down:

4.55 * 1013
4.55 * 1000

and

1.78*1012
1.78*1000

then take them away

so:

4.55*1000= 4550
1.78*1000= 1780 -
                =  2770
                = 2.77*10^3
The antarctic iceberg's mass is approximately 2.77×10³ times bigger than the mass of the rock of Gibraltar.