title: Show result of an operation (multiplication) in textblock
body: <p>I have a textblock, a button and a textbox.
  What I want is the user enter data in a textbox (only numbers - whole numbers or decimals) and press the button appears on the textblock the result of an operation (multiplication) based on the value that the user entered.</p>
  
  <p>For exemple (Button Click Event)
  int num = TextBox.Text;
  TextBlock.Text = num * 0.02;</p>
  
  <p>What I want is: the user enters in the TextBox a decimal or integer (eg 50), when you press the button want to appear in the TextBlock the value that the user entered * 0.02. The result to appear is 1</p>