Runs a function for each element of the array
Creates a new array by running a function on each element
The "filter" creates a new array with the elements that passes a test
"Reduce" runs a function on each element to produce "reduce" the array to a single value
This method does the same as the previous one but starting from the last element of an array.
This test if ALL array elements passes a test
If SOME elements passes a test, returns true