For your better understanding
using System;
using System.Text.RegularExpressions;
namespace myApp
{
class Program
{
static void Main(string[] args)
{
String chk = "5*6";
Match match = Regex.Match(chk, @"(\d)\*(\d)");
Console.WriteLine(match.Groups[0]);
Console.WriteLine(match.Groups[1]);
Console.WriteLine(match.Groups[2]);
}
}
}
Result:
myApp$ dotnet run
5*6
5
6