diff --git a/.gitignore b/.gitignore
index ef21e5d..0eabe3d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,5 @@
 local.properties
 app/release
 /.idea/inspectionProfiles/Project_Default.xml
+/.idea/deploymentTargetSelector.xml
+/.idea/studiobot.xml
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 3c90c5b..08b5324 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -16,7 +16,7 @@
         android:theme="@style/Theme.Android101">
 
         <receiver
-            android:name=".vibrationBroadcastReceiver.vibrationBroadcastReceiver"
+            android:name=".misc.vibrationBroadcastReceiver.vibrationBroadcastReceiver"
             android:enabled="true"
             android:exported="true"
             android:permission="android.permission.VIBRATE">
diff --git a/app/src/main/java/uk/kagurach/android101/MainActivity.java b/app/src/main/java/uk/kagurach/android101/MainActivity.java
index 691c7d7..15707d5 100644
--- a/app/src/main/java/uk/kagurach/android101/MainActivity.java
+++ b/app/src/main/java/uk/kagurach/android101/MainActivity.java
@@ -25,6 +25,8 @@ import androidx.core.view.WindowInsetsCompat;
 
 import java.util.Arrays;
 
+import uk.kagurach.android101.helper.PageHelper;
+
 public class MainActivity extends AppCompatActivity {
     PageHelper pageHelper;
 
diff --git a/app/src/main/java/uk/kagurach/android101/MainActivity2.java b/app/src/main/java/uk/kagurach/android101/MainActivity2.java
index eb47bef..d5b4b03 100644
--- a/app/src/main/java/uk/kagurach/android101/MainActivity2.java
+++ b/app/src/main/java/uk/kagurach/android101/MainActivity2.java
@@ -4,7 +4,6 @@ import android.annotation.SuppressLint;
 import android.content.Context;
 import android.graphics.Color;
 import android.os.Bundle;
-import android.os.IBinder;
 import android.util.TypedValue;
 import android.view.MotionEvent;
 import android.view.View;
@@ -21,7 +20,9 @@ import androidx.appcompat.app.AppCompatActivity;
 import androidx.core.graphics.Insets;
 import androidx.core.view.ViewCompat;
 import androidx.core.view.WindowInsetsCompat;
-import androidx.room.util.StringUtil;
+
+import uk.kagurach.android101.helper.PageHelper;
+import uk.kagurach.android101.helper.ToastHelper;
 
 public class MainActivity2 extends AppCompatActivity {
 
diff --git a/app/src/main/java/uk/kagurach/android101/Page3.java b/app/src/main/java/uk/kagurach/android101/Page3.java
index 8abb09c..bbf10df 100644
--- a/app/src/main/java/uk/kagurach/android101/Page3.java
+++ b/app/src/main/java/uk/kagurach/android101/Page3.java
@@ -1,6 +1,6 @@
 package uk.kagurach.android101;
 
-import static uk.kagurach.android101.KaculateKt.Kaculate;
+import static uk.kagurach.android101.misc.KaculateKt.Kaculate;
 
 import android.os.Bundle;
 import android.view.View;
@@ -14,6 +14,8 @@ import androidx.core.graphics.Insets;
 import androidx.core.view.ViewCompat;
 import androidx.core.view.WindowInsetsCompat;
 
+import uk.kagurach.android101.helper.PageHelper;
+
 public class Page3 extends AppCompatActivity {
 
     PageHelper pageHelper;
diff --git a/app/src/main/java/uk/kagurach/android101/Page4.java b/app/src/main/java/uk/kagurach/android101/Page4.java
index 5885318..78c5152 100644
--- a/app/src/main/java/uk/kagurach/android101/Page4.java
+++ b/app/src/main/java/uk/kagurach/android101/Page4.java
@@ -19,7 +19,8 @@ import androidx.core.graphics.Insets;
 import androidx.core.view.ViewCompat;
 import androidx.core.view.WindowInsetsCompat;
 
-import uk.kagurach.android101.vibrationBroadcastReceiver.vibrationBroadcastReceiver;
+import uk.kagurach.android101.helper.PageHelper;
+import uk.kagurach.android101.misc.vibrationBroadcastReceiver.vibrationBroadcastReceiver;
 
 public class Page4 extends AppCompatActivity {
 
diff --git a/app/src/main/java/uk/kagurach/android101/Page4OtherActivity.java b/app/src/main/java/uk/kagurach/android101/Page4OtherActivity.java
index 302665b..d30d035 100644
--- a/app/src/main/java/uk/kagurach/android101/Page4OtherActivity.java
+++ b/app/src/main/java/uk/kagurach/android101/Page4OtherActivity.java
@@ -8,6 +8,8 @@ import android.util.Log;
 
 import androidx.appcompat.app.AppCompatActivity;
 
+import uk.kagurach.android101.helper.ToastHelper;
+
 public class Page4OtherActivity extends AppCompatActivity {
 
     @Override
diff --git a/app/src/main/java/uk/kagurach/android101/Page5.java b/app/src/main/java/uk/kagurach/android101/Page5.java
index c2f18c1..dfa70a7 100644
--- a/app/src/main/java/uk/kagurach/android101/Page5.java
+++ b/app/src/main/java/uk/kagurach/android101/Page5.java
@@ -21,7 +21,9 @@ import java.io.IOException;
 import java.util.Objects;
 
 import chatgpt.AnimalDatabaseHelper;
-import uk.kagurach.android101.misc.AutoCompleHelper.AnimalTypeAutoCompleteHelper;
+import uk.kagurach.android101.helper.PageHelper;
+import uk.kagurach.android101.helper.ToastHelper;
+import uk.kagurach.android101.helper.AutoCompleHelper.AnimalTypeAutoCompleteHelper;
 
 public class Page5 extends AppCompatActivity {
 
diff --git a/app/src/main/java/uk/kagurach/android101/misc/AutoCompleHelper/AbstractAutoCompleteHelper.java b/app/src/main/java/uk/kagurach/android101/helper/AutoCompleHelper/AbstractAutoCompleteHelper.java
similarity index 98%
rename from app/src/main/java/uk/kagurach/android101/misc/AutoCompleHelper/AbstractAutoCompleteHelper.java
rename to app/src/main/java/uk/kagurach/android101/helper/AutoCompleHelper/AbstractAutoCompleteHelper.java
index 598a96c..decbfe1 100644
--- a/app/src/main/java/uk/kagurach/android101/misc/AutoCompleHelper/AbstractAutoCompleteHelper.java
+++ b/app/src/main/java/uk/kagurach/android101/helper/AutoCompleHelper/AbstractAutoCompleteHelper.java
@@ -1,4 +1,4 @@
-package uk.kagurach.android101.misc.AutoCompleHelper;
+package uk.kagurach.android101.helper.AutoCompleHelper;
 
 import android.content.Context;
 import android.widget.ArrayAdapter;
diff --git a/app/src/main/java/uk/kagurach/android101/misc/AutoCompleHelper/AnimalTypeAutoCompleteHelper.java b/app/src/main/java/uk/kagurach/android101/helper/AutoCompleHelper/AnimalTypeAutoCompleteHelper.java
similarity index 95%
rename from app/src/main/java/uk/kagurach/android101/misc/AutoCompleHelper/AnimalTypeAutoCompleteHelper.java
rename to app/src/main/java/uk/kagurach/android101/helper/AutoCompleHelper/AnimalTypeAutoCompleteHelper.java
index 3be1d23..2a32b37 100644
--- a/app/src/main/java/uk/kagurach/android101/misc/AutoCompleHelper/AnimalTypeAutoCompleteHelper.java
+++ b/app/src/main/java/uk/kagurach/android101/helper/AutoCompleHelper/AnimalTypeAutoCompleteHelper.java
@@ -1,4 +1,4 @@
-package uk.kagurach.android101.misc.AutoCompleHelper;
+package uk.kagurach.android101.helper.AutoCompleHelper;
 
 import android.content.Context;
 import android.widget.ArrayAdapter;
diff --git a/app/src/main/java/uk/kagurach/android101/PageHelper.java b/app/src/main/java/uk/kagurach/android101/helper/PageHelper.java
similarity index 92%
rename from app/src/main/java/uk/kagurach/android101/PageHelper.java
rename to app/src/main/java/uk/kagurach/android101/helper/PageHelper.java
index 75f8515..2292b5b 100644
--- a/app/src/main/java/uk/kagurach/android101/PageHelper.java
+++ b/app/src/main/java/uk/kagurach/android101/helper/PageHelper.java
@@ -1,4 +1,4 @@
-package uk.kagurach.android101;
+package uk.kagurach.android101.helper;
 
 import static androidx.core.content.ContextCompat.startActivity;
 
@@ -16,14 +16,14 @@ public class PageHelper {
     private final Class<?> _next;
     private Activity _activity = null;
 
-    PageHelper(Context curr, Class<?> prev, Class<?> next) {
+    public PageHelper(Context curr, Class<?> prev, Class<?> next) {
         _curr = curr;
         _prev = prev;
         _next = next;
     }
 
 
-    PageHelper(Context curr, Class<?> prev, Class<?> next, Activity activity) {
+    public PageHelper(Context curr, Class<?> prev, Class<?> next, Activity activity) {
         _curr = curr;
         _prev = prev;
         _next = next;
diff --git a/app/src/main/java/uk/kagurach/android101/ToastHelper.kt b/app/src/main/java/uk/kagurach/android101/helper/ToastHelper.kt
similarity index 94%
rename from app/src/main/java/uk/kagurach/android101/ToastHelper.kt
rename to app/src/main/java/uk/kagurach/android101/helper/ToastHelper.kt
index 6d9ca6b..10505bb 100644
--- a/app/src/main/java/uk/kagurach/android101/ToastHelper.kt
+++ b/app/src/main/java/uk/kagurach/android101/helper/ToastHelper.kt
@@ -1,4 +1,4 @@
-package uk.kagurach.android101
+package uk.kagurach.android101.helper
 
 import android.content.Context
 import android.widget.Toast
diff --git a/app/src/main/java/uk/kagurach/android101/Kaculate.kt b/app/src/main/java/uk/kagurach/android101/misc/Kaculate.kt
similarity index 92%
rename from app/src/main/java/uk/kagurach/android101/Kaculate.kt
rename to app/src/main/java/uk/kagurach/android101/misc/Kaculate.kt
index de3d0aa..dac3337 100644
--- a/app/src/main/java/uk/kagurach/android101/Kaculate.kt
+++ b/app/src/main/java/uk/kagurach/android101/misc/Kaculate.kt
@@ -1,6 +1,7 @@
-package uk.kagurach.android101
+package uk.kagurach.android101.misc
 
 import android.content.Context
+import uk.kagurach.android101.helper.ToastHelper
 import kotlin.math.pow
 
 fun Kaculate(src: String, ctx: Context): String {
@@ -14,6 +15,13 @@ fun Kaculate(src: String, ctx: Context): String {
 
     var _curnum = ""
 
+    // Fix for expression starts with operator
+    val src = if (src[0] in OpList){
+        "0" + src
+    }else{
+        src
+    }
+
     for (i in src.indices) {
         if (src[i] in '0'..'9' || src[i] == '.') {
             _curnum += src[i]
diff --git a/app/src/main/java/uk/kagurach/android101/vibrationBroadcastReceiver/vibrationBroadcastReceiver.java b/app/src/main/java/uk/kagurach/android101/misc/vibrationBroadcastReceiver/vibrationBroadcastReceiver.java
similarity index 93%
rename from app/src/main/java/uk/kagurach/android101/vibrationBroadcastReceiver/vibrationBroadcastReceiver.java
rename to app/src/main/java/uk/kagurach/android101/misc/vibrationBroadcastReceiver/vibrationBroadcastReceiver.java
index 9330be8..53dbae0 100644
--- a/app/src/main/java/uk/kagurach/android101/vibrationBroadcastReceiver/vibrationBroadcastReceiver.java
+++ b/app/src/main/java/uk/kagurach/android101/misc/vibrationBroadcastReceiver/vibrationBroadcastReceiver.java
@@ -1,4 +1,4 @@
-package uk.kagurach.android101.vibrationBroadcastReceiver;
+package uk.kagurach.android101.misc.vibrationBroadcastReceiver;
 
 import android.content.BroadcastReceiver;
 import android.content.Context;