diff --git a/kjg/python-the-hard-way/e21.py b/kjg/python-the-hard-way/e21.py
new file mode 100644
index 0000000..a72984f
--- /dev/null
+++ b/kjg/python-the-hard-way/e21.py
@@ -0,0 +1,40 @@
+def add(a, b):
+    print(f"ADDING {a} + {b}")
+    return a + b
+
+
+def subtract(a, b):
+    print(f"SUBTRACTING {a} - {b}")
+    return a - b
+
+
+def multiplay(a, b):
+    print(f"MULTIPLYING {a} * {b}")
+    return a * b
+
+
+def divide(a, b):
+    print(f"DIVIDING {a} / {b}")
+    return a / b
+
+
+print("Let's do some math with just functions!")
+
+age = add(30, 5)
+height = subtract(78, 4)
+weight = multiplay(90, 2)
+iq = divide(100, 2)
+
+print(f"Age: {age}, Height: {height}, Weight: {weight}, IQ: {iq}")
+
+# A puzzle for the extra credit, type it in anyway.
+print("Here is a puzzle.")
+
+what = add(age, subtract(height, multiplay(weight, divide(iq, 2))))
+
+print("That becomes: ", what, "Can you do it by hand?")
+
+
+
+
+
diff --git a/kjg/python.org b/kjg/python.org
index aa4fc79..48b693d 100644
--- a/kjg/python.org
+++ b/kjg/python.org
@@ -94,3 +94,5 @@ How to use function
 How to use function and variables
 **** ex20
 How to use function with file
+**** ex21
+How to use fucntion with return