diff --git a/__pycache__/exercise.cpython-36.pyc b/__pycache__/exercise.cpython-36.pyc
new file mode 100644
index 0000000..278f6a7
Binary files /dev/null and b/__pycache__/exercise.cpython-36.pyc differ
diff --git a/exercise.py b/exercise.py
index 0ae90ce..0815a1a 100644
--- a/exercise.py
+++ b/exercise.py
@@ -4,9 +4,14 @@
 
 
 def sort_by_last_name(people, order):
+    """
+    Doctests:
+        >>> sort_by_last_name(['Bob Smith', 'Ken Jones', 'Alex Bradino'], True)
+        ['Smith, Bob', 'Jones, Ken', 'Bradino, Alex']
+    """
     # return full names sorted by last name in either ascending or descending order
     # add doctests make sure it passes
-    pass
+    return sorted([n.split(" ")[1] +", " + n.split(" ")[0] for n in people], reverse = order)
 
 
 # problem 2
@@ -16,10 +21,14 @@ def sort_by_last_name(people, order):
 
 
 def create_dictionary_from_lists(names, ages):
+    """
+    Doctests:
+        >>> create_dictionary_from_lists(['James', 'Susan', 'Maggie'], [4, 9, 12])
+        {'James': 4, 'Susan': 9, 'Maggie': 12}
+    """
     # {'James':4, 'Susan':9, 'Maggie':12}
     # add doctests make sure it passes
-    pass
-
+    return {n:a for n, a in zip(names, ages)}
 
 # problem 3
 # ------------------------------------------------------------------- #
@@ -27,6 +36,13 @@ def create_dictionary_from_lists(names, ages):
 
 
 def square_even_values_and_sum_under_10(numbers):
+    """
+    Argument: List of numbers
+    Return int
+    Doctests:
+        >>> square_even_values_and_sum_under_10([5, 6, 7, 8, 9, 10, 11, 12])
+        100
+    """
     # 6^2 + 8^2]
     # add doctests make sure it passes
-    pass
+    return sum([n**2 for n in numbers if n % 2 == 0 and n < 10])