JavaScript please

1. Write a function and test code for each of the following

   1. Write a function that takes a Celsius temperature and returns a Fahrenheit temperature. The formula is F = (9.0/5.0) * C + 32.0.

   2. Write a function that takes an array of numbers and returns the sum of the numbers.

   3. Write a function that takes a test grade score (0-100) and returns the letter grade for that score, using the standard 90,80,70,60 grading scale.