MainWindow.xaml

<Window x:Class="Calculator.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:Calculator"
        mc:Ignorable="d"
        Title="Calculatorinator" Height="600" Width="450">
    <Window.Resources>

    </Window.Resources>

    <Grid Margin="10">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*"/>
            <ColumnDefinition Width="*"/>
            <ColumnDefinition Width="*"/>
            <ColumnDefinition Width="*"/>
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="2*"/>
            <RowDefinition Height="*"/>
            <RowDefinition Height="*"/>
            <RowDefinition Height="*"/>
            <RowDefinition Height="*"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <Label x:Name="labelResult"
               Content="0" 
               Grid.Column="0"
               Grid.ColumnSpan="4"
               VerticalAlignment="Bottom"
               HorizontalAlignment="Right"/>
        <Button x:Name="buttonAC"
                Style="{StaticResource AdditionalButtons}"
                Content="AC"
                Grid.Row="1"
                Click="ButtonAC_Click"/>
        <Button x:Name="button7"
                Style="{StaticResource numberButtonsStyle}"
                Content="7"
                Grid.Row="2"
                Click="ButtonNumber_Click"/>
        <Button x:Name="button4"
                Style="{StaticResource numberButtonsStyle}"
                Content="4"
                Grid.Row="3"
                Click="ButtonNumber_Click"/>
        <Button x:Name="button1"
                Style="{StaticResource numberButtonsStyle}"
                Content="1"
                Grid.Row="4"
                Click="ButtonNumber_Click"/>
        <Button x:Name="buttonNegative"
                Style="{StaticResource AdditionalButtons}"
                Content="+/-"
                Grid.Row="1"
                Grid.Column="1"
                Click="ButtonNegative_Click"/>
        <Button x:Name="button8"
                Style="{StaticResource numberButtonsStyle}"
                Content="8"
                Grid.Column="1"
                Grid.Row="2"
                Click="ButtonNumber_Click"/>
        <Button x:Name="button5"
                Style="{StaticResource numberButtonsStyle}"
                Content="5"
                Grid.Column="1"
                Grid.Row="3"
                Click="ButtonNumber_Click"/>
        <Button x:Name="button2"
                Style="{StaticResource numberButtonsStyle}"
                Content="2"
                Grid.Column="1"
                Grid.Row="4"
                Click="ButtonNumber_Click"/>
        <Button x:Name="buttonMod"
                Style="{StaticResource AdditionalButtons}"
                Content="%"
                Grid.Column="2"
                Grid.Row="1"
                Click="OperationButton_Click"/>
        <Button x:Name="button9"
                Style="{StaticResource numberButtonsStyle}"
                Content="9"
                Grid.Column="2"
                Grid.Row="2"
                Click="ButtonNumber_Click"/>
        <Button x:Name="button6"
                Style="{StaticResource numberButtonsStyle}"
                Content="6"
                Grid.Column="2"
                Grid.Row="3"
                Click="ButtonNumber_Click"/>
        <Button x:Name="button3"
                Style="{StaticResource numberButtonsStyle}"
                Content="3"
                Grid.Column="2"
                Grid.Row="4"
                Click="ButtonNumber_Click"/>
        <Button x:Name="buttonDivision"
                Style="{StaticResource operatorsButtonsStyle}"
                Content="/"
                Grid.Column="3"
                Grid.Row="1"
                Click="OperationButton_Click"/>
        <Button x:Name="buttonMultiplication"
                Style="{StaticResource operatorsButtonsStyle}"
                Content="*"
                Grid.Column="3"
                Grid.Row="2"
                Click="OperationButton_Click"/>
        <Button x:Name="buttonSubtraction"
                Style="{StaticResource operatorsButtonsStyle}"
                Content="-"
                Grid.Column="3"
                Grid.Row="3"
                Click="OperationButton_Click"/>
        <Button x:Name="buttonAddition"
                Style="{StaticResource operatorsButtonsStyle}"
                Content="+"
                Grid.Column="3"
                Grid.Row="4"
                Click="OperationButton_Click"/>
        <Button x:Name="buttonEquals"
                Style="{StaticResource operatorsButtonsStyle}"
                Content="="
                Grid.Column="3"
                Grid.Row="5"
                Click="ButtonEquals_Click"/>
        <Button x:Name="buttonDecimal"
                Style="{StaticResource numberButtonsStyle}"
                Content="."
                Grid.Column="2"
                Grid.Row="5"
                Click="ButtonDecimal_Click"/>
        <Button x:Name="button0"
                Style="{StaticResource numberButtonsStyle}"
                Content="0"
                Grid.ColumnSpan="2"
                Grid.Row="5"
                Click="ButtonNumber_Click"/>
    </Grid>
</Window>