title: operator * cannot be applied to decimal and double c#
body: <p>I am currently making a tax program (study project) that read in a CSV file and generates a list of people and account balances, i need to round down 2 decimal places from one text box and add them up in another text box. my code attached tell me i cannot use " * " how do i times a decimal with 0.1? and if i am doing this wrong let me know, cheers!</p>
  
  <pre><code>public partial class Form1 : Form
  {
      //CSV ARRAY LISTS
      List&lt;string&gt; fullName = new List&lt;string&gt;();
      List&lt;string&gt; accBalance = new List&lt;string&gt;();
  
      int currentItem;
      int index;
      int counter = 0;
  
      decimal interestBalance = 0;
      decimal result;
  
      decimal interestRemainder = 0;
      double round = 0.1;
  
  
   private void interestBalanceBox_TextChanged(object sender, EventArgs e)
      {
          interestRemainder = decimal.Parse(interestBalanceBox.Text);
          interestRemainder = Math.Truncate(0.1 * interestRemainder) / 100;
          interestRemainderBox.Text = interestRemainder.ToString();
  
      }
  </code></pre>
  
  <p>the program we are meant to represent is this one here! any help would be much appreciated.</p>
  
  <p><a href="https://i.stack.imgur.com/XQxgf.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/XQxgf.jpg" alt="enter image description here"></a></p>