title: Calculate checksum in C#
body: <pre><code>numbers[i] = numbers[i] * 2;
  
  if (numbers[i] &gt;= 10)
  {
     string t = numbers[i].ToString();
     Console.WriteLine(t[0] + " plus " + t[1]+" = "+quersumme(t).ToString());
     numbers[i] = Convert.ToInt32(t[0]) + Convert.ToInt32(t[1]);
  }
  
  public int quersumme(string n)
  {
     return n[0] + n[1];
  }
  </code></pre>
  
  <p>The function returns 101 when I enter 7. But 7 * 2 = 14 and quersumme should do 1+4 = 5</p>