Astronomers measure large distances in light-years. One light-year is the distance that light can travel in one year, or approximately 5,880,000,000,000 miles. Suppose a star is 13.6 light-years from Earth. In scientific notation, how many miles away is it?

Answer 1

I entered the numbers in my calculator, which you could
have done just as well,
and came up with 7.9968 x 10^13

Answer 2

We don't use calculators, is the issue.