diff --git a/.idea/misc.xml b/.idea/misc.xml
index 59436c9..9076de5 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -3,7 +3,7 @@
   <component name="EntryPointsManager">
     <entry_points version="2.0" />
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_7" assert-keyword="true" jdk-15="true" project-jdk-name="1.7" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_7" assert-keyword="true" jdk-15="true" project-jdk-name="1.8" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/build/classes" />
   </component>
 </project>
diff --git a/.idea/modules.xml b/.idea/modules.xml
index 2f72ee4..e69c0ed 100644
--- a/.idea/modules.xml
+++ b/.idea/modules.xml
@@ -3,6 +3,7 @@
   <component name="ProjectModuleManager">
     <modules>
       <module fileurl="file://$PROJECT_DIR$/Lab2Exercise1.iml" filepath="$PROJECT_DIR$/Lab2Exercise1.iml" />
+      <module fileurl="file://$PROJECT_DIR$/Lab2Exercise1_Wed.iml" filepath="$PROJECT_DIR$/Lab2Exercise1_Wed.iml" />
       <module fileurl="file://$PROJECT_DIR$/app/app.iml" filepath="$PROJECT_DIR$/app/app.iml" />
     </modules>
   </component>
diff --git a/.idea/vcs.xml b/.idea/vcs.xml
index def6a6a..9d32e50 100644
--- a/.idea/vcs.xml
+++ b/.idea/vcs.xml
@@ -2,6 +2,7 @@
 <project version="4">
   <component name="VcsDirectoryMappings">
     <mapping directory="" vcs="" />
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
   </component>
 </project>
 
diff --git a/Lab2Exercise1_Wed.iml b/Lab2Exercise1_Wed.iml
new file mode 100644
index 0000000..2a02201
--- /dev/null
+++ b/Lab2Exercise1_Wed.iml
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module external.linked.project.path="$MODULE_DIR$" external.root.project.path="$MODULE_DIR$" external.system.id="GRADLE" type="JAVA_MODULE" version="4">
+  <component name="FacetManager">
+    <facet type="java-gradle" name="Java-Gradle">
+      <configuration>
+        <option name="BUILD_FOLDER_PATH" value="$MODULE_DIR$/build" />
+      </configuration>
+    </facet>
+  </component>
+  <component name="NewModuleRootManager" inherit-compiler-output="false">
+    <output url="file://$MODULE_DIR$/build/classes/main" />
+    <output-test url="file://$MODULE_DIR$/build/classes/test" />
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <excludeFolder url="file://$MODULE_DIR$/.gradle" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>
+
diff --git a/app/src/main/java/th/ac/tu/siit/its333/lab2exercise1/MainActivity.java b/app/src/main/java/th/ac/tu/siit/its333/lab2exercise1/MainActivity.java
index f3d87ed..b51857e 100644
--- a/app/src/main/java/th/ac/tu/siit/its333/lab2exercise1/MainActivity.java
+++ b/app/src/main/java/th/ac/tu/siit/its333/lab2exercise1/MainActivity.java
@@ -14,6 +14,7 @@ public class MainActivity extends ActionBarActivity {
 
     // expr = the current string to be calculated
     StringBuffer expr;
+    int memory =0;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -28,6 +29,44 @@ public void updateExprDisplay() {
         tvExpr.setText(expr.toString());
     }
 
+    public void memoryHandle(View v)
+    {
+        int id = v.getId();
+        TextView tvAns = (TextView)findViewById(R.id.tvAns);
+        switch(id){
+            case R.id.madd:
+                int memadd = Integer.parseInt(tvAns.getText().toString());
+                memory+=memadd;
+                Toast t1 = Toast.makeText(this.getApplicationContext(),
+                        "Memory Added, Value="+memory, Toast.LENGTH_SHORT);
+                t1.show();
+                break;
+            case R.id.msub:
+                int memsub = Integer.parseInt(tvAns.getText().toString());
+                memory-=memsub;
+                Toast t2 = Toast.makeText(this.getApplicationContext(),
+                        "Memory Subtracted, Value="+memory, Toast.LENGTH_SHORT);
+                t2.show();
+                break;
+            case R.id.mr:
+                TextView tvExpr = (TextView)findViewById(R.id.tvExpr);
+                tvAns.setText(Integer.toString(memory));
+                Toast t3 = Toast.makeText(this.getApplicationContext(),
+                        "Memory Showed", Toast.LENGTH_SHORT);
+                expr = new StringBuffer(Integer.toString(memory));
+                updateExprDisplay();
+                t3.show();
+                break;
+            case R.id.mc:
+                memory = 0;
+                Toast t4 = Toast.makeText(this.getApplicationContext(),
+                        "Memory Cleared, Value="+memory, Toast.LENGTH_SHORT);
+                t4.show();
+                break;
+            default: break;
+        }
+    }
+
     public void recalculate() {
         //Calculate the expression and display the output
 
@@ -36,6 +75,40 @@ public void recalculate() {
         //reference: http://stackoverflow.com/questions/2206378/how-to-split-a-string-but-also-keep-the-delimiters
         String e = expr.toString();
         String[] tokens = e.split("((?<=\\+)|(?=\\+))|((?<=\\-)|(?=\\-))|((?<=\\*)|(?=\\*))|((?<=/)|(?=/))");
+        TextView tvAns = (TextView)findViewById(R.id.tvAns);
+        if(tokens.length == 1)
+        {
+            tvAns.setText(tokens[0]);
+        }
+        else
+        {
+            if(tokens.length%2 == 1)
+            {
+               int result = Integer.parseInt(tokens[0]);
+               for(int i=1;i<tokens.length;i+=2)
+               {
+                   String operator = tokens[i];
+                   int operand = Integer.parseInt(tokens[i+1]);
+                   if(operator.equals("+"))
+                   {
+                     result+=operand;
+                   }
+                   if(operator.equals("-"))
+                   {
+                     result-=operand;
+                   }
+                   if(operator.equals("*"))
+                   {
+                     result*=operand;
+                   }
+                   if(operator.equals("/"))
+                   {
+                     result/=operand;
+                   }
+               }
+               tvAns.setText(Integer.toString(result));
+            }
+        }
     }
 
     public void digitClicked(View v) {
@@ -51,14 +124,33 @@ public void digitClicked(View v) {
 
     public void operatorClicked(View v) {
         //IF the last character in expr is not an operator and expr is not "",
-        //THEN append the clicked operator and updateExprDisplay,
-        //ELSE do nothing
+        if(expr.length()!=0)
+        {
+            char last = expr.charAt(expr.length() - 1);
+            if (last != '+' && last != '-' && last != '*' && last != '/')
+            {
+                //THEN append the clicked operator and updateExprDisplay,
+                String d = ((TextView) v).getText().toString();
+                expr.append(d);
+                updateExprDisplay();
+            }
+        }
+    }
+
+    public void equalClicked(View v){
+        TextView tvAns = (TextView)findViewById(R.id.tvAns);
+        String result = tvAns.getText().toString();
+        expr = new StringBuffer(result);
+        updateExprDisplay();
+        tvAns.setText("0");
     }
 
     public void ACClicked(View v) {
         //Clear expr and updateExprDisplay
         expr = new StringBuffer();
         updateExprDisplay();
+        TextView tvAns = (TextView)findViewById(R.id.tvAns);
+        tvAns.setText(expr.toString());
         //Display a toast that the value is cleared
         Toast t = Toast.makeText(this.getApplicationContext(),
                 "All cleared", Toast.LENGTH_SHORT);
@@ -70,6 +162,7 @@ public void BSClicked(View v) {
         if (expr.length() > 0) {
             expr.deleteCharAt(expr.length()-1);
             updateExprDisplay();
+            recalculate();
         }
     }
 
diff --git a/app/src/main/res/layout/activity_main.xml b/app/src/main/res/layout/activity_main.xml
index a895ff2..37da49a 100644
--- a/app/src/main/res/layout/activity_main.xml
+++ b/app/src/main/res/layout/activity_main.xml
@@ -73,7 +73,8 @@
             android:id="@+id/madd"
             android:layout_row="3"
             android:layout_column="0"
-            android:textSize="28sp" />
+            android:textSize="28sp"
+            android:onClick="memoryHandle" />
 
         <Button
             android:layout_width="wrap_content"
@@ -82,7 +83,8 @@
             android:id="@+id/msub"
             android:layout_row="3"
             android:layout_column="1"
-            android:textSize="28sp" />
+            android:textSize="28sp"
+            android:onClick="memoryHandle" />
 
         <Button
             android:layout_width="wrap_content"
@@ -91,7 +93,8 @@
             android:id="@+id/mr"
             android:layout_row="3"
             android:layout_column="2"
-            android:textSize="28sp" />
+            android:textSize="28sp"
+            android:onClick="memoryHandle" />
 
         <Button
             android:layout_width="wrap_content"
@@ -100,7 +103,8 @@
             android:id="@+id/mc"
             android:layout_row="3"
             android:layout_column="3"
-            android:textSize="28sp" />
+            android:textSize="28sp"
+            android:onClick="memoryHandle" />
 
         <Button
             android:layout_width="wrap_content"