// just two decimal places
String.Format("{0:0.00}", 123.4567); // "123.46"
String.Format("{0:0.00}", 123.4); // "123.40"
String.Format("{0:0.00}", 123.0); // "123.00"
http://www.csharp-examples.net/string-format-double/
edit
No idea why they used "String" instead of "string", but the rest is correct.