diff --git a/javaSE-day08/src/com/inmind/digui02/Demo09.java b/javaSE-day08/src/com/inmind/digui02/Demo09.java
index dc638ca..757f46a 100644
--- a/javaSE-day08/src/com/inmind/digui02/Demo09.java
+++ b/javaSE-day08/src/com/inmind/digui02/Demo09.java
@@ -27,7 +27,7 @@ n=1就是结束条件
 public class Demo09 {
     public static void main(String[] args) {
      //计算5的阶乘
-        System.out.println(getJieCheng(5));
+        System.out.println(getJieCheng(3));
     }
 
     //定义求n的阶乘的功能方法
@@ -39,5 +39,4 @@ public class Demo09 {
         //2.如果不是结束条件,那么按数学规律或者逻辑规律调用自己
         return n*getJieCheng(n-1);
     }
-
 }
diff --git a/javaSE-day08/src/com/inmind/digui02/Demo10.java b/javaSE-day08/src/com/inmind/digui02/Demo10.java
new file mode 100644
index 0000000..fd27a8a
--- /dev/null
+++ b/javaSE-day08/src/com/inmind/digui02/Demo10.java
@@ -0,0 +1,29 @@
+package com.inmind.digui02;
+/*
+    递归求累和的练习
+    5的累和:5+4+3+2+1 = 15
+    4的累和:4+3+2+1 = 10
+    3的累和:3+2+1 = 6
+    2的累和:2+1 = 3
+    1的累和:1
+
+    规律：n的累和：n+(n-1)的累和
+    结束条件：1的累和就是1
+
+ */
+public class Demo10 {
+    public static void main(String[] args) {
+        //100的累和是多少
+        System.out.println(getSum(100));
+    }
+
+    //计算n的累和
+    public static int getSum(int n) {
+        //结束条件：1的累和就是1
+        if (n == 1) {
+            return 1;
+        }
+        //规律：n的累和：n+(n-1)的累和
+        return n + getSum(n - 1);
+    }
+}