diff --git a/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/Calculator/Implementation/Calculator.cs b/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/Calculator/Implementation/Calculator.cs
index 03701980..8ded816c 100644
--- a/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/Calculator/Implementation/Calculator.cs
+++ b/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/Calculator/Implementation/Calculator.cs
@@ -2,7 +2,6 @@
 using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Input;
-using System.Windows.Media;
 using System.Windows.Threading;
 using Microsoft.Windows.Controls.Core.Utilities;
 
@@ -16,10 +15,9 @@ namespace Microsoft.Windows.Controls
         private readonly DispatcherTimer _timer;
         private Button _calculatorButton;
 
-        bool _showNewNumber = true;
-        decimal _previousValue;
-        CalculatorButtonType _lastButtonPressed;
-        Operation _lastOperation = Operation.None;
+        private bool _showNewNumber = true;
+        private decimal _previousValue;
+        private Operation _lastOperation = Operation.None;
 
         #endregion //Members
 
@@ -37,19 +35,19 @@ namespace Microsoft.Windows.Controls
             Equal,
             Five,
             Four,
-            Fract,
+            Fraction,
             MAdd,
             MC,
             MR,
             MS,
             MSub,
             Multiply,
+            Negate,
             Nine,
             None,
             One,
             Percent,
             Seven,
-            Sign,
             Six,
             Sqrt,
             Subtract,
@@ -64,7 +62,12 @@ namespace Microsoft.Windows.Controls
             Subtract,
             Divide,
             Multiply,
-            None
+            Percent,
+            Sqrt,
+            Fraction,
+            None,
+            Clear,
+            Negate
         }
 
         #endregion //Enumerations
@@ -178,7 +181,7 @@ namespace Microsoft.Windows.Controls
             var buttonType = CalculatorUtilities.GetCalculatorButtonTypeFromText(e.Text);
             if (buttonType != CalculatorButtonType.None)
             {
-                AnimateCalculatorButtonClick(buttonType);
+                SimulateCalculatorButtonClick(buttonType);
                 ProcessCalculatorButton(buttonType);
             }
         }
@@ -202,23 +205,12 @@ namespace Microsoft.Windows.Controls
 
         #region Methods
 
-        private void AnimateCalculatorButtonClick(CalculatorButtonType buttonType)
-        {
-            _calculatorButton = CalculatorUtilities.FindButtonByCalculatorButtonType(_buttonPanel, buttonType);
-            VisualStateManager.GoToState(_calculatorButton, "Pressed", true);
-            _timer.Start();
-        }
-
         private void ProcessCalculatorButton(CalculatorButtonType buttonType)
         {
             if (CalculatorUtilities.IsDigit(buttonType))
                 ProcessDigit(buttonType);
-            else if (CalculatorUtilities.IsOperation(buttonType))
-                ProcessOperation(buttonType);
             else
-                ProcessMisc(buttonType);
-
-            _lastButtonPressed = buttonType;
+                ProcessOperation(buttonType);
         }
 
         private void ProcessDigit(CalculatorButtonType buttonType)
@@ -232,57 +224,51 @@ namespace Microsoft.Windows.Controls
         }
 
         private void ProcessOperation(CalculatorButtonType buttonType)
-        {
-            if (_lastButtonPressed != CalculatorButtonType.Add &&
-                _lastButtonPressed != CalculatorButtonType.Subtract &&
-                _lastButtonPressed != CalculatorButtonType.Multiply &&
-                _lastButtonPressed != CalculatorButtonType.Divide)
-            {
-
-                Operation operation = Operation.None;
-
-                switch (buttonType)
-                {
-                    case CalculatorButtonType.Add:
-                        operation = Operation.Add;
-                        break;
-                    case CalculatorButtonType.Subtract:
-                        operation = Operation.Subtract;
-                        break;
-                    case CalculatorButtonType.Multiply:
-                        operation = Operation.Multiply;
-                        break;
-                    case CalculatorButtonType.Divide:
-                        operation = Operation.Divide;
-                        break;
-                    default:
-                        operation = Operation.None;
-                        break;
-                }
-
-                Calculate();
-
-                _previousValue = Decimal.Parse(DisplayText);
-
-                _showNewNumber = true;
-                _lastOperation = operation;
-            }
-        }
-
-        private void ProcessMisc(CalculatorButtonType buttonType)
         {
             switch (buttonType)
             {
-                case CalculatorButtonType.Clear:
-                    Value = decimal.Zero;
-                    _showNewNumber = true;
+                case CalculatorButtonType.Add:
+                    Calculate(Operation.Add);
+                    break;
+                case CalculatorButtonType.Subtract:
+                    Calculate(Operation.Subtract);
+                    break;
+                case CalculatorButtonType.Multiply:
+                    Calculate(Operation.Multiply);
+                    break;
+                case CalculatorButtonType.Divide:
+                    Calculate(Operation.Divide);
+                    break;
+                case CalculatorButtonType.Percent:
+                    Calculate(Operation.Percent);
+                    break;
+                case CalculatorButtonType.Sqrt:
+                    Calculate(Operation.Sqrt, Operation.None);
+                    break;
+                case CalculatorButtonType.Fraction:
+                    Calculate(Operation.Fraction, Operation.None);
+                    break;
+                case CalculatorButtonType.Negate:
+                    Calculate(Operation.Negate, Operation.None);
                     break;
                 case CalculatorButtonType.Equal:
-                    Calculate();
+                    Calculate(Operation.None);
+                    break;
+                case CalculatorButtonType.Clear:                    
+                    Calculate(Operation.Clear, Operation.None);
+                    DisplayText = Value.ToString();
+                    break;
+                case CalculatorButtonType.Cancel:
+                    DisplayText = _previousValue.ToString();
                     _lastOperation = Operation.None;
                     _showNewNumber = true;
+                    return;
+                default:
                     break;
             }
+
+            _previousValue = Decimal.Parse(DisplayText);
+            _showNewNumber = true;
         }
 
         private void Calculate()
@@ -293,23 +279,65 @@ namespace Microsoft.Windows.Controls
             Value = CalculateValue(_lastOperation);
         }
 
+        private void Calculate(Operation newOperation)
+        {
+            if (!_showNewNumber)
+                Calculate();
+
+            _lastOperation = newOperation;
+        }
+
+        private void Calculate(Operation currentOperation, Operation newOperation)
+        {
+            _lastOperation = currentOperation;
+            Calculate();
+            _lastOperation = newOperation;
+        }
+
         private decimal CalculateValue(Operation operation)
         {
+            decimal newValue = decimal.Zero;
             decimal currentValue = Decimal.Parse(DisplayText);
 
             switch (operation)
             {
                 case Operation.Add:
-                   return CalculatorUtilities.Add(_previousValue, currentValue);
+                    newValue = CalculatorUtilities.Add(_previousValue, currentValue);
+                    break;
                 case Operation.Subtract:
-                    return CalculatorUtilities.Subtract(_previousValue, currentValue);
+                    newValue = CalculatorUtilities.Subtract(_previousValue, currentValue);
+                    break;
                 case Operation.Multiply:
-                    return CalculatorUtilities.Multiply(_previousValue, currentValue);
+                    newValue = CalculatorUtilities.Multiply(_previousValue, currentValue);
+                    break;
                 case Operation.Divide:
-                    return CalculatorUtilities.Divide(_previousValue, currentValue);
+                    newValue = CalculatorUtilities.Divide(_previousValue, currentValue);
+                    break;
+                case Operation.Percent:
+                    newValue = CalculatorUtilities.Percent(_previousValue, currentValue);
+                    break;
+                case Operation.Sqrt:
+                    newValue = CalculatorUtilities.SquareRoot(currentValue);
+                    break;
+                case Operation.Fraction:
+                    newValue = CalculatorUtilities.Fraction(currentValue);
+                    break;
+                case Operation.Negate:
+                    newValue = CalculatorUtilities.Negate(currentValue);
+                    break;
                 default:
-                    return decimal.Zero;
+                    newValue = decimal.Zero;
+                    break;
             }
+
+            return newValue;
+        }
+
+        private void SimulateCalculatorButtonClick(CalculatorButtonType buttonType)
+        {
+            _calculatorButton = CalculatorUtilities.FindButtonByCalculatorButtonType(_buttonPanel, buttonType);
+            VisualStateManager.GoToState(_calculatorButton, "Pressed", true);
+            _timer.Start();
         }
 
         #endregion //Methods
diff --git a/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/Calculator/Themes/Generic.xaml b/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/Calculator/Themes/Generic.xaml
index b07215ec..89b4969c 100644
--- a/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/Calculator/Themes/Generic.xaml
+++ b/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/Calculator/Themes/Generic.xaml
@@ -339,7 +339,7 @@
                                     Style="{StaticResource CalculatorOperatorButtonStyle}"/>
 
             <Button Grid.Column="6" Grid.Row="2" MinWidth="28" MinHeight="26"
-                                    local:Calculator.CalculatorButtonType="Sign"
+                                    local:Calculator.CalculatorButtonType="Negate"
                                     Command="local:CalculatorCommands.CalculatorButtonClick"
                                     Style="{StaticResource CalculatorOperatorButtonStyle}"/>
 
@@ -394,7 +394,7 @@
                                     Style="{StaticResource CalculatorOperatorButtonStyle}"/>
 
             <Button Grid.Column="8" Grid.Row="6" MinWidth="28" MinHeight="26"
-                                    local:Calculator.CalculatorButtonType="Fract"
+                                    local:Calculator.CalculatorButtonType="Fraction"
                                     Command="local:CalculatorCommands.CalculatorButtonClick"
                                     Style="{StaticResource CalculatorOperatorButtonStyle}"/>
 
@@ -455,6 +455,10 @@
         <Setter Property="Template">
             <Setter.Value>
                 <ControlTemplate TargetType="{x:Type local:Calculator}">
+                    <Grid>
+                        <Grid.RowDefinitions>
+                            <RowDefinition Height="Auto" />
+                        </Grid.RowDefinitions>
                     <Border Background="{TemplateBinding Background}"
                             BorderBrush="{TemplateBinding BorderBrush}"
                             BorderThickness="{TemplateBinding BorderThickness}"
@@ -473,6 +477,7 @@
                             <ContentControl x:Name="PART_CalculatorButtonPanel" Grid.Row="1" Template="{StaticResource CalculatorButtonPanel}" DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}" />
                         </Grid>
                     </Border>
+                    </Grid>
                     <!--<ControlTemplate.Triggers>
                         <Trigger Property="IsFocused" Value="True">
                             <Setter TargetName="PART_Display" Property="Background" Value="#E7F5FF" />
diff --git a/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/Core/Utilities/CalculatorUtilities.cs b/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/Core/Utilities/CalculatorUtilities.cs
index d7575eb1..34ec43c3 100644
--- a/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/Core/Utilities/CalculatorUtilities.cs
+++ b/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/Core/Utilities/CalculatorUtilities.cs
@@ -97,7 +97,7 @@ namespace Microsoft.Windows.Controls.Core.Utilities
                 case Calculator.CalculatorButtonType.Four:
                     content = "4";
                     break;
-                case Calculator.CalculatorButtonType.Fract:
+                case Calculator.CalculatorButtonType.Fraction:
                     content = "1/x";
                     break;
                 case Calculator.CalculatorButtonType.MAdd:
@@ -132,7 +132,7 @@ namespace Microsoft.Windows.Controls.Core.Utilities
                 case Calculator.CalculatorButtonType.Seven:
                     content = "7";
                     break;
-                case Calculator.CalculatorButtonType.Sign:
+                case Calculator.CalculatorButtonType.Negate:
                     content = "+/-";
                     break;
                 case Calculator.CalculatorButtonType.Six:
@@ -187,12 +187,16 @@ namespace Microsoft.Windows.Controls.Core.Utilities
                 case Calculator.CalculatorButtonType.Multiply:
                 case Calculator.CalculatorButtonType.Divide:
                 case Calculator.CalculatorButtonType.Percent:
+                case Calculator.CalculatorButtonType.Sqrt:
+                case Calculator.CalculatorButtonType.Fraction:
                     return true;
                 default:
                     return false;
             }
         }
 
+        //TODO: add error handling
+
         public static decimal Add(decimal firstNumber, decimal secondNumber)
         {
             return firstNumber + secondNumber;
@@ -212,5 +216,25 @@ namespace Microsoft.Windows.Controls.Core.Utilities
         {
             return firstNumber / secondNumber;
         }
+
+        public static decimal Percent(decimal firstNumber, decimal secondNumber)
+        {
+            return firstNumber * secondNumber / 100M;
+        }
+
+        public static decimal SquareRoot(decimal operand)
+        {
+            return Convert.ToDecimal(Math.Sqrt(Convert.ToDouble(operand)));
+        }
+
+        public static decimal Fraction(decimal operand)
+        {
+            return 1 / operand;
+        }
+
+        public static decimal Negate(decimal operand)
+        {
+            return operand * -1M;
+        }
     }
 }