diff --git a/app/src/main/java/uk/kagurach/android101/Kaculate.kt b/app/src/main/java/uk/kagurach/android101/Kaculate.kt
index b75d025..9bf48f7 100644
--- a/app/src/main/java/uk/kagurach/android101/Kaculate.kt
+++ b/app/src/main/java/uk/kagurach/android101/Kaculate.kt
@@ -1,7 +1,104 @@
 package uk.kagurach.android101
 
 import android.content.Context
+import kotlin.math.pow
 
 fun Kaculate(src: String,ctx :Context) : String{
-    return ""
+    if (src.isBlank()){
+        return src
+    }
+
+    val OpList = charArrayOf('+','-','x','/','^')
+    var numStack = floatArrayOf()
+    var opStack  = charArrayOf()
+
+    var _curnum = ""
+
+    var _immediatePop = false
+    for (i in 0..<src.length){
+        if (src[i] in '0'..'9' || src[i] == '.'){
+            _curnum += src[i]
+        }
+        else if (src[i] in OpList){
+            try {
+                numStack += _curnum.toFloat()
+                _curnum = ""
+            }catch (e:Exception){
+                ToastHelper.ShowToast(e.toString(),ctx)
+                return src
+            }
+
+            if (_immediatePop){
+                try {
+                    val exp = numStack.last()
+                    numStack.dropLast(1)
+                    val num = numStack.last()
+                    numStack.dropLast(1)
+
+                    numStack += num.pow(exp)
+                    _immediatePop = false
+                }catch (e:Exception){
+                    ToastHelper.ShowToast(e.toString(),ctx)
+                    return src
+                }
+            }
+
+            if (src[i] == '^'){
+                _immediatePop = true
+            }else{
+                opStack += src[i]
+            }
+        }
+        else{
+            ToastHelper.ShowToast("Unknown input char:" + src[i].toString(),ctx);
+            return src
+        }
+    }
+
+    if (_curnum.isNotEmpty()){
+        try {
+            numStack += _curnum.toFloat()
+            _curnum = ""
+        }catch (e:Exception){
+            ToastHelper.ShowToast(e.toString(),ctx)
+            return src
+        }
+    }
+
+    if (numStack.size != opStack.size+1 ){
+        ToastHelper.ShowToast("Ops and nums Not Match!",ctx)
+        return src
+    }
+
+    var intStackCurr = 0
+    for (i in 0..<opStack.size){
+        if (opStack[i] == 'x'){
+            val a = numStack[intStackCurr]
+            val b = numStack[intStackCurr+1]
+            numStack[intStackCurr] = a*b
+            numStack.drop(intStackCurr+1)
+            opStack.drop(i)
+        }else if (opStack[i] == '/'){
+            val a = numStack[intStackCurr]
+            val b = numStack[intStackCurr+1]
+            numStack[intStackCurr] = a/b
+            numStack.drop(intStackCurr+1)
+            opStack.drop(i)
+        }else{
+            intStackCurr ++
+        }
+    }
+    if (opStack.size!=0) {
+        for (i in opStack) {
+            if (i == '+') {
+                numStack[0] += numStack[1]
+                numStack.drop(1)
+            } else {
+                numStack[0] -= numStack[1]
+                numStack.drop(1)
+            }
+        }
+    }
+
+    return numStack[0].toString()
 }
\ No newline at end of file
diff --git a/app/src/main/java/uk/kagurach/android101/MainActivity.java b/app/src/main/java/uk/kagurach/android101/MainActivity.java
index ad82dd5..54d3d04 100644
--- a/app/src/main/java/uk/kagurach/android101/MainActivity.java
+++ b/app/src/main/java/uk/kagurach/android101/MainActivity.java
@@ -38,7 +38,7 @@ public class MainActivity extends AppCompatActivity {
         super.onResume();
 
         TextView tv = findViewById(R.id.tv_hello);
-        textViewAppendString(tv,"Starting Kagura Init");
+        textViewAppendString(tv,"Starting Initialize");
         if (Build.VERSION.SDK_INT >= 33) {
             textViewAppendString(tv,"Find api > 33, checking permission");
             if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.POST_NOTIFICATIONS) != PackageManager.PERMISSION_GRANTED) {
diff --git a/app/src/main/java/uk/kagurach/android101/Page3.java b/app/src/main/java/uk/kagurach/android101/Page3.java
index f41c849..f81f7d5 100644
--- a/app/src/main/java/uk/kagurach/android101/Page3.java
+++ b/app/src/main/java/uk/kagurach/android101/Page3.java
@@ -13,7 +13,6 @@ import androidx.core.graphics.Insets;
 import androidx.core.view.ViewCompat;
 import androidx.core.view.WindowInsetsCompat;
 
-import uk.kagurach.android101.KaculateKt;
 public class Page3 extends AppCompatActivity {
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -43,7 +42,7 @@ public class Page3 extends AppCompatActivity {
         findViewById(R.id.P3Dot).setOnClickListener(new CalculateOnClickListener());
         findViewById(R.id.P3CE).setOnClickListener(new CalculateOnClickListener());
         findViewById(R.id.P3ChengFang).setOnClickListener(new CalculateOnClickListener());
-        findViewById(R.id.P3Result).setOnClickListener(new CalculateOnClickListener());
+        findViewById(R.id.P3EqualButton).setOnClickListener(new CalculateOnClickListener());
     }
 
 
@@ -74,7 +73,7 @@ public class Page3 extends AppCompatActivity {
     }
 
     private void calc(){
-        TextView textView = findViewById(R.id.P3Result);
+        TextView textView = findViewById(R.id.P3CalcResult);
         String result = Kaculate(textView.getText().toString(),this);
         textView.setText(result);
     }
diff --git a/app/src/main/res/layout/activity_page3.xml b/app/src/main/res/layout/activity_page3.xml
index 88230d4..5c5221c 100644
--- a/app/src/main/res/layout/activity_page3.xml
+++ b/app/src/main/res/layout/activity_page3.xml
@@ -189,7 +189,7 @@
                 android:text="." />
 
             <Button
-                android:id="@+id/P3Result"
+                android:id="@+id/P3EqualButton"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:layout_row="4"