diff --git a/README.md b/README.md
index 8fe711203..645eccf4a 100644
--- a/README.md
+++ b/README.md
@@ -17,6 +17,7 @@
 3. Git 브랜치를 master 또는 main으로 변경한 후 피드백을 반영하기 위한 새로운 브랜치를 생성한 후 처음부터 다시 미션 구현을 도전한다.
 
 ```
+
 git branch -a // 모든 로컬 브랜치 확인
 git checkout master // 기본 브랜치가 master인 경우
 git checkout main // 기본 브랜치가 main인 경우
@@ -24,3 +25,18 @@ git checkout main // 기본 브랜치가 main인 경우
 git checkout -b 브랜치이름
 ex) git checkout -b apply-feedback
 ```
+4.구현할 기능 목록
+1~9까지의 서로 다른 3자리 맞추는거
+
+~~게임 시작
+1. 게임이 시작되면 컴퓨터가 1~9까지의 수 중 중복없는 3자리 수를 랜덤으로 생성
+2. "숫자를 입력해 주세요 : " 라는 문구와 함께 사용자로부터 입력 받기
+3. 사용자가 유효하지 않은 수를 입력했을시 예외처리
+4. 사용자가 입력한 수와 컴퓨터의 수를 비교하여 스트라이크, 볼 계산
+5. 2~4번을 반복문으로 돌리고, 만약 정답이라면 게임종료 문구를 출력, 아니라면 계속 진행
+6. 게임 종료 후 게임을 다시 시작하냐는 문구 출력, 사용자 입력 받음
+7. 사용자 입력에 따라 다시 시작 / 게임 종료 / 
+8. 사용자가 유효하지 않은 숫자 입력 시 예외처리 
+
+------------------------
+
diff --git a/src/main/java/baseballgame/Application.java b/src/main/java/baseballgame/Application.java
new file mode 100644
index 000000000..8eff0e137
--- /dev/null
+++ b/src/main/java/baseballgame/Application.java
@@ -0,0 +1,38 @@
+package baseballgame;
+
+import java.util.List;
+public class Application {
+    public void res_equals(String result, List<Integer> com_num){
+        Compare compare = new Compare();
+        playgame game = new playgame();
+        while(!result.equals("3strike")) {
+            result = compare.Compare_num(com_num, game.player_num());
+            System.out.println(result);
+        }
+    }
+    public static void main(String[] args) throws IllegalArgumentException{
+        try{
+            ComputerNum computer = new ComputerNum();
+            playgame game = new playgame();
+            Compare compare = new Compare();
+            Regame regame = new Regame();
+            Application app = new Application();
+
+            boolean again = true;
+
+            while(again) {
+                List<Integer> com_num = computer.ComputerNumber();
+                List<Integer> player_num = game.player_num();
+
+                String result = "";
+                app.res_equals(result,com_num);
+
+                again = regame.restart();
+            }
+        } catch (IllegalArgumentException e) {
+            System.out.println(e.getMessage());
+            return;
+        }
+
+    }
+}
diff --git a/src/main/java/baseballgame/Compare.java b/src/main/java/baseballgame/Compare.java
new file mode 100644
index 000000000..bc49541ac
--- /dev/null
+++ b/src/main/java/baseballgame/Compare.java
@@ -0,0 +1,38 @@
+package baseballgame;
+
+import java.util.List;
+
+public class Compare {
+    public int count(List<Integer> computer, List<Integer> player) {
+        int count = 0;
+
+        for(int i = 0; i < player.size(); i++) {
+            if(computer.contains(player.get(i))) {
+                count++;
+            }
+        }
+        return count;
+    }
+
+    public int Strikecount(List<Integer> computer, List<Integer> player) {
+        int strike = 0;
+
+        for(int i = 0; i < player.size(); i++) {
+            if(computer.get(i) == player.get(i)) {
+                strike++;
+            }
+        }
+        return strike;
+    }
+
+    public String Compare_num(List<Integer> computer, List<Integer> player) {
+        int count = count(computer, player);
+        int strike = Strikecount(computer, player);
+        int ball = count - strike;
+
+        if(count == 0) return "nothing";
+        else if(strike == 0) return ball + "ball";
+        else if(ball == 0) return strike + "strike";
+        else return ball + "ball " + strike + "strike";
+    }
+}
diff --git a/src/main/java/baseballgame/ComputerNum.java b/src/main/java/baseballgame/ComputerNum.java
new file mode 100644
index 000000000..236755108
--- /dev/null
+++ b/src/main/java/baseballgame/ComputerNum.java
@@ -0,0 +1,21 @@
+package baseballgame;
+
+
+import java.util.Random;
+import java.util.ArrayList;
+import java.util.List;
+
+public class ComputerNum {
+    Random random = new Random();
+    public List<Integer> ComputerNumber(){
+
+        List<Integer> com_num = new ArrayList<>(); // Create list contains answer
+        while (com_num.size() < 3) {
+            int randNum = random.nextInt(10);
+            if (!com_num.contains(randNum)) {
+                com_num.add(randNum);
+            }
+        }
+        return com_num;
+    }
+}
diff --git a/src/main/java/baseballgame/Regame.java b/src/main/java/baseballgame/Regame.java
new file mode 100644
index 000000000..3c69bf0f5
--- /dev/null
+++ b/src/main/java/baseballgame/Regame.java
@@ -0,0 +1,21 @@
+package baseballgame;
+
+import java.util.Scanner;
+
+public class Regame {
+    public boolean restart(){
+        System.out.println("you corrected 3 number! end game");
+        System.out.println("enter 1 to restart game, enter 2 to exit game");
+
+        Scanner scanner = new Scanner(System.in);
+        char answer = scanner.next().charAt(0);
+
+        if(answer == '1') {
+            return true;
+        } else if (answer == '2') {
+            return false;
+        }else{
+            throw new IllegalArgumentException("enter 1 or 2");
+        }
+    }
+}
diff --git a/src/main/java/baseballgame/playgame.java b/src/main/java/baseballgame/playgame.java
new file mode 100644
index 000000000..672171c7c
--- /dev/null
+++ b/src/main/java/baseballgame/playgame.java
@@ -0,0 +1,31 @@
+package baseballgame;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+
+public class playgame {
+    Scanner scanner = new Scanner(System.in);
+    public List<Integer> player_num() {
+
+        System.out.println("Enter Number : ");
+        List<Integer> player_num = new ArrayList<>();
+        String input = String.valueOf(scanner.nextInt());
+
+        for(int i=0; i<input.length(); i++){
+            int digit = Character.getNumericValue(input.charAt(i));
+            if (!player_num.contains(digit)) {
+                player_num.add(Integer.parseInt(String.valueOf(digit)));
+          }
+        }
+
+        Length_exception(input);
+        return player_num;
+    }
+    public void Length_exception(String s){
+        if(s.length() != 3) {
+            throw new IllegalArgumentException("Not a three digit number");
+        }
+    }
+
+}
diff --git a/src/test/java/baseballgame/ApplicationTest.java b/src/test/java/baseballgame/ApplicationTest.java
new file mode 100644
index 000000000..2fce78fcc
--- /dev/null
+++ b/src/test/java/baseballgame/ApplicationTest.java
@@ -0,0 +1,170 @@
+package baseballgame;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.io.ByteArrayInputStream;
+import java.util.Arrays;
+import java.util.List;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+import static org.junit.jupiter.api.Assertions.*;
+
+class ApplicationTest {
+
+    @Test
+    @DisplayName("Test Duplication in com_num")
+    public void com_num_Dup_test(){
+        //given
+        List<Integer> com_num;
+
+        //when
+        ComputerNum computer = new ComputerNum();
+        com_num = computer.ComputerNumber();
+
+        //then
+        assertNotEquals(com_num.get(0),com_num.get(1));
+        assertNotEquals(com_num.get(1),com_num.get(2));
+        assertNotEquals(com_num.get(0),com_num.get(2));
+    }
+
+    @Test
+    @DisplayName("3Strike Test")
+    public void strike3Test(){
+        List<Integer> test1 = Arrays.asList(1,2,3);
+        List<Integer> test2 = Arrays.asList(1,2,3);
+
+        Compare compare = new Compare();
+
+        assertEquals("3strike", compare.Compare_num(test1,test2));
+    }
+
+    @Test
+    @DisplayName("3ball Test")
+    public void ball3Test(){
+        List<Integer> test1 = Arrays.asList(1,2,3);
+        List<Integer> test2 = Arrays.asList(2,3,1);
+
+        Compare compare = new Compare();
+
+        assertEquals("3ball", compare.Compare_num(test1,test2));
+    }
+
+    @Test
+    @DisplayName("nothing Test")
+    public void nothingTest(){
+        List<Integer> test1 = Arrays.asList(1,2,3);
+        List<Integer> test2 = Arrays.asList(4,5,6);
+
+        Compare compare = new Compare();
+
+        assertEquals("nothing", compare.Compare_num(test1,test2));
+    }
+
+    @Test
+    @DisplayName("N Strike 0 Ball Test")
+    public void NStrike0BallTest(){
+        List<Integer> test1 = Arrays.asList(1,2,3);
+        List<Integer> test2 = Arrays.asList(1,5,6);
+
+        Compare compare = new Compare();
+
+        assertEquals("1strike", compare.Compare_num(test1,test2));
+    }
+
+    @Test
+    @DisplayName("0 Strike N Ball Test")
+    public void NBall0StrikeTest(){
+        List<Integer> test1 = Arrays.asList(1,2,3);
+        List<Integer> test2 = Arrays.asList(5,1,6);
+
+        Compare compare = new Compare();
+
+        assertEquals("1ball", compare.Compare_num(test1,test2));
+    }
+
+    @Test
+    @DisplayName("N Strike N Ball Test")
+    public void NStrikeNBallTest(){
+        List<Integer> test1 = Arrays.asList(1,2,3);
+        List<Integer> test2 = Arrays.asList(1,6,2);
+
+        Compare compare = new Compare();
+
+        assertEquals("1ball 1strike", compare.Compare_num(test1,test2));
+    }
+
+    @Test
+    @DisplayName("player input exception test")
+    public void testLength_exception_whenInputLengthIsGreaterThanThree() {
+        playgame playgame = new playgame();
+
+        try {
+            playgame.Length_exception("1234");
+            fail("Expected IllegalArgumentException");
+        } catch (IllegalArgumentException e) {
+            assertEquals("Not a three digit number", e.getMessage());
+        }
+    }
+
+    @Test
+    public void testLength_exception_whenInputLengthIsThree() {
+        playgame playgame = new playgame();
+        try {
+            playgame.Length_exception("123");
+        } catch (IllegalArgumentException e) {
+            fail("Unexpected IllegalArgumentException");
+        }
+    }
+
+    @Test
+    public void testLength_exception_whenInputLengthIsLessThanThree() {
+        playgame playgame = new playgame();
+        try {
+            playgame.Length_exception("12");
+            fail("Expected IllegalArgumentException");
+        } catch (IllegalArgumentException e) {
+            assertEquals("Not a three digit number", e.getMessage());
+        }
+    }
+
+    @Test
+    public void testRestart_Input1() {
+        String input = "1";
+        System.setIn(new ByteArrayInputStream(input.getBytes()));
+
+        Regame regame = new Regame();
+        boolean result = regame.restart();
+
+        assertTrue(result);
+    }
+
+    @Test
+    public void testRestart_whenInputIs2() {
+        String input = "2";
+        System.setIn(new ByteArrayInputStream(input.getBytes()));
+
+        Regame regame = new Regame();
+        boolean result = regame.restart();
+
+        assertFalse(result);
+    }
+
+    @Test
+    public void testRestart_whenInputIsInvalid() {
+        String input = "3"; // Invalid input
+        System.setIn(new ByteArrayInputStream(input.getBytes()));
+
+        Regame regame = new Regame();
+
+        try {
+            regame.restart();
+            fail("Expected IllegalArgumentException");
+        } catch (IllegalArgumentException e) {
+            assertEquals("enter 1 or 2", e.getMessage());
+        }
+    }
+
+
+
+}
\ No newline at end of file
diff --git a/src/test/java/study/StringTest.java b/src/test/java/study/StringTest.java
index 43e47d90b..c154a55e7 100644
--- a/src/test/java/study/StringTest.java
+++ b/src/test/java/study/StringTest.java
@@ -9,5 +9,6 @@ public class StringTest {
     void replace() {
         String actual = "abc".replace("b", "d");
         assertThat(actual).isEqualTo("adc");
+
     }
 }