diff --git a/ch03-lists-tuples/e09b5_plus_minus.py b/ch03-lists-tuples/e09b5_plus_minus.py
index 5f738b8..f288a26 100755
--- a/ch03-lists-tuples/e09b5_plus_minus.py
+++ b/ch03-lists-tuples/e09b5_plus_minus.py
@@ -10,12 +10,4 @@ def plus_minus(numbers):
     if not numbers:
         return 0
 
-    total = numbers.pop(0)
-
-    while numbers:
-        total += numbers.pop(0)
-
-        if numbers:
-            total -= numbers.pop(0)
-
-    return total
+    return numbers[0]+sum(numbers[1::2])-sum(numbers[2::2])