Write a program using a function called computegrade that takes

a score as its parameter and returns a grade as a string.

Use the following grading scale

Score Grade $>=0\mathrm{.}9$ A $>=0\mathrm{.}8$ B $>=0\mathrm{.}7$ C $>=0\mathrm{.}6$ D $<0\mathrm{.}6$ F