This service is the numerical version of Cows and Bulls game!
it will randomly generate a 4-digit number without duplicate numbers!
Haven't played Cows and Bulls before?
The built-in teach mode would lead you to understand the rules!
✪Update:
1. Change the infrastructure
2. Added support language
🌐 List of supported languages:
Traditional Chinese (Taiwan), Traditional Chinese (Hong Kong), English, Japanese,Korean,Thai
[Wikipedia definition]
Bulls and Cows is an old code-breaking mind or paper and pencil game for two or more players, predating the commercially marketed board game Mastermind.
For details, you can get it on Wikipedia: https://en.wikipedia.org/wiki/Bulls_and_Cows