diff --git a/chapter_9_9.py b/chapter_9_9.py
new file mode 100644
index 0000000..ff6672a
--- /dev/null
+++ b/chapter_9_9.py
@@ -0,0 +1,22 @@
+cat_hat = {}
+
+# set each cat without a hat
+for cat in range(1,101):
+    cat_hat[cat] = "off"
+
+# walk around that cat circle 100 times (set round 1)    
+rounds = 1
+while rounds <= 100:
+    # for each new round start at 'round' continuing to 100 adding a hat
+    # at each stop.  For round 1 we will stop at each cat
+    for i in range(rounds, 101, rounds):
+        if cat_hat[i] == 'off':
+            cat_hat[i] = 'on'
+        else:
+            cat_hat[i] = 'off'
+    rounds += 1
+for cat in cat_hat:
+    if cat_hat[cat] == 'on':
+        print(f"Cat {cat} has a hat!")
+    else:
+        print(f"Cat {cat} has no hat!")