The code will display decimal values with percent precision, round them to cents.
Then compare the calculation with the original values to the one with rounded values.
Define two fixed value as
double amount1 = 1234.56789; double amount2 = 99.87654321;
Use them as the value to do the rounding
using System; class Program{/*from w w w . jav a 2 s. c o m*/ static void Main(string[] args){ double amount1 = 1234.56789; double amount2 = 99.87654321; // Displaying inputs (original values) Console.WriteLine("First amount (original value): " + amount1); Console.WriteLine("Second amount (original value): " + amount2); // Rounding just for output Console.WriteLine("First amount displayed with cent precision: " + amount1.ToString("N2")); Console.WriteLine("Second amount displayed with cent precision: " + amount2.ToString("N2")); Console.WriteLine(); // Rounding for further calculations + informative output double roundedAmount1 = Math.Round(amount1, 2); // 2 = two decimal places double roundedAmount2 = Math.Round(amount2, 2); Console.WriteLine("First amount rounded to cents: " + roundedAmount1); Console.WriteLine("Second amount rounded to cents: " + roundedAmount2); Console.WriteLine(); // Calculations double sumOfOriginalAmounts = amount1 + amount2; double sumOfRoundedAmounts = roundedAmount1 + roundedAmount2; // Calculation outputs Console.WriteLine("Sum of original amounts: " + sumOfOriginalAmounts. ToString("N2")); Console.WriteLine("Sum of rounded amounts: " + sumOfRoundedAmounts. ToString("N2")); Console.WriteLine("On invoice, we need sum of rounded amounts"); } }