namespace InvoiceTotal { public partial class frmInvoiceTotal : Form { public frmInvoiceTotal() { InitializeComponent(); } private void btnCalculate_Click(object sender, EventArgs e) { decimal subtotal = Decimal.Parse(txtSubtotal.Text); // Converted this expression to parse decimal discountPercent = .25m; decimal discountAmount = Math.Round(subtotal * discountPercent, 2); decimal invoiceTotal = Math.Round(subtotal - discountAmount, 2); txtDiscountPercent.Text = discountPercent.ToString("p1"); txtDiscountAmount.Text = discountAmount.ToString("c"); txtTotal.Text = invoiceTotal.ToString("c"); txtSubtotal.Focus(); } private void btnExit_Click(object sender, EventArgs e) { this.Close(); } } }