The distance between earth and jupiter at the closest point is 5.9 × 108 kilometers, and the distance between earth and mercury at the closest point is 7.7 × 107 kilometers. the closest distance between earth and is greater than the closest distance between earth and by approximately times.

I think the last sentence has blanks we're supposed to fill in:

The closest distance between Earth and _________ is greater than the closest distance between Earth and ______ by approximately _______ times.

The distance to Jupiter is greater, so that goes in the first blank, Mercury in the second.  The third gets the quotient of the distances:



The closest distance between Earth and Jupiter  is greater than the closest distance between Earth and Mercury  by approximately 7.66 times.