diff --git a/2_intermediate/chapter11/practice/number_mystery_1.py b/2_intermediate/chapter11/practice/number_mystery_1.py
new file mode 100644
index 00000000..5b01f798
--- /dev/null
+++ b/2_intermediate/chapter11/practice/number_mystery_1.py
@@ -0,0 +1,12 @@
+# Number Mystery 1
+# Write a function called num_mystery that takes in 3 integers.
+# The function should calculate the sum of the 3 integers and
+# the difference between the largest integer and the smallest integer.
+# The function should return the product of these two integers you calculated.
+#
+# Hint: You may find it useful to use the max() and min() functions.
+#
+# Use the num_mystery function on 1, 2, 3 and print the result.
+# Use the num_mystery function on 5, 13, 7 and print the result.
+
+# write code here