ใบแจ้งหนี้และการจัดรูปแบบตัวเลข

using System;
class Program
{
    static void Main()
    {
        var lines = new[] { ("Book", 2, 12.50m), ("Pen", 3, 1.25m) };
        foreach (var (name, quantity, price) in lines)
            Console.WriteLine($"{name,-8} {quantity,2} {quantity * price,8:F2}");
    }
}