Create easyChallenge3.txt

a) Write a function, which returns the factorial of a number. console.log(a(6)); should return 720.

b) Make a function that adds up all the numbers up to and including an inputtted number. Eg addUp(5) returns 15. Try to include basic error handling, for example if you input "hello" instead of a number it should realize it!

c) Create a function adding together all the squares of the numbers up to and including an inputted number.

d) Write a function, which returns the nth fibonacci number. The formula for fibonacci numbers: n = (n-1)+(n-2). They begin with the numbers 1 and 1, then 2, then 3, then 5 and so on.