diff --git a/day02/src/com/inmind/operator02/Demo09.java b/day02/src/com/inmind/operator02/Demo09.java
new file mode 100644
index 0000000..877d8b0
--- /dev/null
+++ b/day02/src/com/inmind/operator02/Demo09.java
@@ -0,0 +1,23 @@
+package com.inmind.operator02;
+/*
+9.运算符_赋值运算符:
+=
+混合赋值运算
++=,-=,*=,/=,%=
+
+混合赋值运算：先将左边的变量与右边的数值进行对应的运算，将运算结果赋值给左边的变量
+*/
+public class Demo09 {
+    public static void main(String[] args) {
+        int i = 10;
+        i = i + 5;
+        System.out.println(i);//15
+
+        //使用混合赋值运算
+        i += 5;//类似于i = i + 5;
+        System.out.println(i);//20
+
+        i -= 5;
+        System.out.println(i);//15
+    }
+}