C# Evaluate Expression- Mathematical calculation

<asp:TextBox ID="txtEquation" runat="server" MaxLength="50"></asp:TextBox>
                    <asp:Button ID="calculate" runat="server" Text="Calculate" OnClick="calculate_Click" />
                    <asp:Label ID="lblResult" runat="server" Text="0"></asp:Label>

 private object EvaluateExpression(string eqn)
        {
            DataTable dt = new DataTable();
            var result = dt.Compute(eqn, string.Empty);
            return result;
        }

        protected void calculate_Click(object sender, EventArgs e)
        {
            try
            {
                string result = Convert.ToString(EvaluateExpression(txtEquation.Text.Trim()));
                lblResult.Text = "Result: " + String.Format(result, "#.##");
                lblResult.ForeColor = Color.Green;
            }
            catch (Exception ex)
            {
                lblResult.Text = "Oops!! error occured: " + ex.Message.ToString();
                lblResult.ForeColor = Color.Red;
            }
        }

OutPut is: