diff --git a/day02/src/com/inmind/yunsuanfu02/Demo07.java b/day02/src/com/inmind/yunsuanfu02/Demo07.java
index 90c326b..75e4b02 100644
--- a/day02/src/com/inmind/yunsuanfu02/Demo07.java
+++ b/day02/src/com/inmind/yunsuanfu02/Demo07.java
@@ -1,4 +1,24 @@
 package com.inmind.yunsuanfu02;
+/*
+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 Demo07 {
+    public static void main(String[] args) {
+        int i = 10;
+        //在变量i的基础上+5,重新赋值给i
+//        i = i +5;
+        i += 5;
+        System.out.println(i);
+
+        i-=10;// i =  i - 10
+        System.out.println(i);
+
+        i%=2;// i = i%2;
+        System.out.println(i);//1
+    }
 }