arrayAddition.rb

# Arrays provide a variety of methods that allow to add elements to them.

# push allows one to add an element to the end of the list.
 x = [1,2]
 x.push(3)
#  => [1,2,3]

# insert allows one to add one or more elements starting from a given index (shifting elements after the given index in the process).
 x = [1,2]
 x.insert(1, 5, 6, 7)
#  => [1, 5, 6, 7, 2]

# unshift allows one or more elements to be added at the beginning of the list.
 x = [1,2,3]
 x.unshift(10, 20, 30)
#  => [10, 20, 30, 1, 2, 3]

#solution
def end_arr_add(arr, element)
  # Add `element` to the end of the Array variable `arr` and return `arr`
  arr.push(element)
end

def begin_arr_add(arr, element)
  # Add `element` to the beginning of the Array variable `arr` and return `arr`
  arr.unshift(element)
end

def index_arr_add(arr, index, element)
  # Add `element` at position `index` to the Array variable `arr` and return `arr`
  arr.insert(index,element)
end

def index_arr_multiple_add(arr, index)
  # add any two elements to the arr at the index
  arr.insert(index,index+1,index+2)
end