Bulls and Cows : the number game 🔢

Bulls and cows is an app version of old paper and pencil mind game. With the help of hints, decode the secret number.
In addition to usual 4-digits numbers, the game is available to be played with any number of digits from 2 to 9.
Player needs to identify the secret number with help of Bulls and Cows(hints). He/she starts by submitting a random number as a guess and then he/she gets the count of bulls and cows of his/her guessed number.
Bulls are matching digits that are placed in their right positions.
Cows are matching digits that are placed in different positions.
• Secret number: 9835
i) Player's guess: 1234
⇒ 1
ull ("3" is the bull)
ii) Player's guess: 5678
⇒ Answer: 2
ows ("5" and "8" are cows)
iii) Player's guess: 9530
⇒ 2
ulls and 1
ow ("9" and "3" are bulls, "5" is cow)
iv) Player's guess: 9835
⇒ 4
ulls
• 0️⃣ cost - absolutely free.
• 1️⃣ of the most lightweight number game, with apk size of less than 3 MB.
• 2️⃣ modes - practice and game.
• 3️⃣ difficulty levels in each stage.
• 5️⃣ rewards in each stage.
• 8️⃣ stages - beginning from 2-digits numbers and ending at 9️⃣ digits numbers.