diff --git a/serie1/IT19ta_ZH7_S1_Aufg3.py b/serie1/IT19ta_ZH7_S1_Aufg3.py
index e8b6c1f..3facced 100755
--- a/serie1/IT19ta_ZH7_S1_Aufg3.py
+++ b/serie1/IT19ta_ZH7_S1_Aufg3.py
@@ -1,4 +1,37 @@
 #!/usr/bin/env python3
+import numpy as np
+import timeit
+
+
+def fact_rec(n):
+    # y = fact_rec(n) berechnet die Fakultät von n als
+    # fact_rec(n) = n * fact_rec(n - 1) mit fact_rec(0) = 1
+    # Fehler, falls n <0 oder nicht ganzzahlig
+    if n < 0 or np.trunc(n) != n:
+        raise Exception('The factorial is defined only for positive integers')
+    if n <= 1:
+        return 1
+    else:
+        return n*fact_rec(n-1)
+
+
+def fact_for(n):
+    fak = 1
+    for num in range(n):
+        fak *= n
+        n -= 1
+    return fak
+
 
 if __name__ == "__main__":
-    pass
+    t1 = timeit.repeat(
+        "fact_rec(500)",
+        "from __main__ import fact_rec",
+        number=100)
+    print(t1)
+
+    t2 = timeit.repeat(
+        "fact_for(500)",
+        "from __main__ import fact_for",
+        number=100)
+    print(t2)