diff --git a/chapter6/Introduce_Explaining_Variable.rb b/chapter6/Introduce_Explaining_Variable.rb
index 60bdf68..8f6c7fe 100644
--- a/chapter6/Introduce_Explaining_Variable.rb
+++ b/chapter6/Introduce_Explaining_Variable.rb
@@ -9,9 +9,8 @@ def price
     # 価格は、基本価格 - 数量割引 + 配送料
     base_price = @quantity * @item_price
     quantity_discount = [0, @quantity - 500].max * @item_price * 0.05
-    return base_price -
-    quantity_discount +
-    [base_price * 0.1,100.0].min
+    shipping = [base_price * 0.1, 100.0].min
+    return base_price - quantity_discount + shipping
   end
 end