MVVM-implementation

I have tried following John Gossman's ContactDatabase-example to make a
simple application to divide a two decimals, just to grasp the concept of the
MVVM-design-pattern. I would like some feeback on it ...

First I have a supersimple Model like this:

public class Model
{
public decimal A;
public decimal B;
}

My ViewModel is a bit more complicated:

public class ViewModel : INotifyPropertyChanged
{
Model model;
decimal result;
ICommand divide;

public ViewModel(Model model)
{
this.model = model;
}

public decimal A
{
get { return model.A; }
set { model.A = value; OnPropertyChanged("A"); }
}

public decimal B
{
get { return model.B; }
set { model.B = value; OnPropertyChanged("B"); }
}

public decimal Result
{
get { return result; }
internal set { result = value; OnPropertyChanged("Result"); }
}

public ICommand Divide
{
get
{
if (divide == null)
divide = new DivideCommand(this);
return divide;
}
}

public event PropertyChangedEventHandler PropertyChanged;
void OnPropertyChanged(string propertyName) { ... }
}

public class DivideCommand : ICommand
{
ViewModel viewModel;

public DivideCommand(ViewModel viewModel)
{
this.viewModel = viewModel;
this.viewModel.PropertyChanged += new
PropertyChangedEventHandler(viewModel_PropertyChanged);
}

void viewModel_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
if (e.PropertyName == "B")
OnCanExecuteChanged();
}

public bool CanExecute(object parameter)
{
return viewModel.B != 0;
}

public event EventHandler CanExecuteChanged;
void OnCanExecuteChanged() { ... }

public void Execute(object parameter)
{
viewModel.Result = viewModel.A / viewModel.B;
}
}

And lastly I have my View:

<Grid x:Name="View" DataContext="..."> // Im setting the DC to a new
ViewModel in App.xaml.cs
<Button Command="{Binding Path=Divide}">Divide</Button>
<TextBox Text="{Binding Path=Result, Mode=OneWay}" />
<Slider Value="{Binding Path=A}" />
<Slider Value="{Binding Path=B}" />
<Label Content="{Binding Path=A, Mode=OneWay}" />
<Label Content="{Binding Path=B, Mode=OneWay}" />
</Grid>

How does this look? Should I have the method to Divide in the model or in
the viewmodel? Any other comments... ?

Thanks in advance!

/Maximilian