public static int Bikoret(string tz)
for(i = 0; i < tz.Length; i++)
temp = ((tz[i] - 48) * 2);
temp = temp % 10 + temp / 10;
public static bool tz_checker(string tz)
for(i = 0; i < tz.Length; i++)
temp = ((tz[i] - 48) * 2);
temp = temp % 10 + temp / 10;
if((tz[tz.Length-1] - 48) == 0)
if((tz[tz.Length-1] - 48) == (10 - (sum % 10)))
public static void Main()
Console.WriteLine("Enter your tz without bikoret num: ");
Console.WriteLine("Your bikoret num is: " + Bikoret(tz));
Console.WriteLine("Enter your tz with bikoret num: ");
Console.WriteLine("Your tz is: " + tz_checker(tz));