diff --git a/SimpleCalculator/CalculatorMV.cs b/SimpleCalculator/CalculatorMV.cs
index 7d29a5f..9c2e2bf 100644
--- a/SimpleCalculator/CalculatorMV.cs
+++ b/SimpleCalculator/CalculatorMV.cs
@@ -5,6 +5,13 @@ namespace SimpleCalculator;
 
 public partial class CalculatorMV : ObservableObject {
 
+    private enum State
+    {
+        Number,
+        Action,
+        Calculate,
+    }
+
     private enum Action {
         None,
         Add,
@@ -13,11 +20,11 @@ public partial class CalculatorMV : ObservableObject {
         Divide,
     }
 
-    private double accumulator = 0;
-    private (Action, double) currentAction = (Action.None, 0);
+    private State currentState = State.Number;
+    private string accumulator = "0";
+    private (Action, string) currentAction = (Action.None, "0");
     private bool isDecimal = false;
     private bool isNegative = false;
-    private bool isResult = false;
 
 
     [ObservableProperty]
@@ -26,10 +33,9 @@ public partial class CalculatorMV : ObservableObject {
 
     [RelayCommand]
     private void numberClicked(string value) {
-        if (this.isResult) {
+        if (this.currentState == State.Action) {
             this.ResultText = "0";
-            this.isResult = false;
-            this.accumulator = double.Parse(value);
+
         }
         if (value == "0" && this.ResultText == "0")
             return;
@@ -37,13 +43,15 @@ public partial class CalculatorMV : ObservableObject {
             this.ResultText = "";
         else if (this.ResultText == "-0")
             this.ResultText = "-";
+        this.currentState = State.Number;
         this.ResultText += value;
     }
 
     [RelayCommand]
     private void acClicked() {
-        this.accumulator = 0;
-        this.currentAction = (Action.None, 0);
+        this.accumulator = "";
+        this.currentState = State.Number;
+        this.currentAction = (Action.None, "");
         this.isDecimal = false;
         this.isNegative = false;
         this.ResultText = "0";
@@ -57,46 +65,47 @@ public partial class CalculatorMV : ObservableObject {
         } else {
             this.isNegative = true;
             this.ResultText = "-" + this.ResultText;
+
         }
     }
 
     [RelayCommand]
     private void percentileClicked() {
-        this.accumulator = double.Parse(this.ResultText);
-        this.accumulator *= 0.01;
-        this.ResultText = this.accumulator.ToString();
+        this.accumulator = this.ResultText;
+        this.accumulator = (double.Parse(this.accumulator) * 0.01).ToString();
+        this.ResultText = this.accumulator;
     }
 
     [RelayCommand]
     private void divideClicked() {
-        var value = double.Parse(this.ResultText);
+        var value = this.ResultText;
         this.currentAction = (Action.Divide, value);
-        this.accumulator = value;
-        this.isResult = true;
+        this.accumulator = "0";
+        this.currentState = State.Action;
     }
 
     [RelayCommand]
     private void multiplyClicked() {
-        var value = double.Parse(this.ResultText);
+        var value =this.ResultText;
         this.currentAction = (Action.Multiply, value);
-        this.accumulator = value;
-        this.isResult = true;
+        this.accumulator = "0";
+        this.currentState = State.Action;
     }
 
     [RelayCommand]
     private void subtractClicked() {
-        var value = double.Parse(this.ResultText);
+        var value = this.ResultText;
         this.currentAction = (Action.Subtract, value);
-        this.accumulator = value;
-        this.isResult = true;
+        this.accumulator = "0";
+        this.currentState = State.Action;
     }
 
     [RelayCommand]
     private void addClicked() {
-        var value = double.Parse(this.ResultText);
+        var value = this.ResultText;
         this.currentAction = (Action.Add, value);
-        this.accumulator = value;
-        this.isResult = true;
+        this.accumulator = "0";
+        this.currentState = State.Action;
     }
 
     [RelayCommand]
@@ -106,20 +115,20 @@ public partial class CalculatorMV : ObservableObject {
             case Action.None:
                 break;
             case Action.Add:
-                this.accumulator = value + this.accumulator;
+                this.accumulator = (double.Parse(value) + double.Parse(this.ResultText)).ToString();
                 break;
             case Action.Subtract:
-                this.accumulator = value - this.accumulator;
+                this.accumulator = (double.Parse(value) - double.Parse(this.ResultText)).ToString();
                 break;
-            case Action.Multiply:
-                this.accumulator = value * this.accumulator;
+            case Action.Multiply: 
+                this.accumulator = (double.Parse(value) * double.Parse(this.ResultText)).ToString();
                 break;
             case Action.Divide:
-                this.accumulator = value / this.accumulator;
+                this.accumulator = (double.Parse(value) / double.Parse(this.ResultText)).ToString();
                 break;
         }
         this.ResultText = this.accumulator.ToString();
-        this.isResult = true;
+        this.currentState = State.Calculate;
     }
 
     [RelayCommand]