diff --git a/README.md b/README.md
index 8fe711203..7b1ce4d13 100644
--- a/README.md
+++ b/README.md
@@ -24,3 +24,30 @@ git checkout main // 기본 브랜치가 main인 경우
 git checkout -b 브랜치이름
 ex) git checkout -b apply-feedback
 ```
+---
+4. 기능 목록 - TDD 구현
+- 1~9의 숫자 중 랜덤으로 3개의 숫자를 구한다
+- 사용자로부터 입력 받는 3개 숫자 예외처리
+  - 1~9의 숫자인가?
+  - 중복 값이 있는가?
+  - 3자리인가?
+- 위치와 숫자 값이 같은 경우 -> 스트라이크
+- 위치는 다른데 숫자 값이 같은 경우 -> 볼
+- 숫자 값이 다른 경우 -> 낫싱
+- 사용자가 입력한 값에 대한 실행 결과를 구한다
+
+```jsx
+com / user
+123 / 123 -> 3 strike
+123 / 142 -> 1 strike, 1 ball
+
+# step 1
+1 2 / 1 2 -> strike
+3 2 / 1 2 -> ball
+1 3 / 1 2 -> nothing
+
+# step 2
+123 / 1 1 -> strike 
+123 / 1 2 -> ball
+123 / 1 5 -> nothing
+```
\ No newline at end of file
diff --git a/src/main/java/baseball/Ball.java b/src/main/java/baseball/Ball.java
new file mode 100644
index 000000000..bcf5eabdb
--- /dev/null
+++ b/src/main/java/baseball/Ball.java
@@ -0,0 +1,35 @@
+package baseball;
+
+public class Ball {
+    // Step 1
+
+    private final int position;
+    private final int ballNum;
+
+    public Ball(int position, int ballNum) {
+        this.position = position;
+        this.ballNum = ballNum;
+    }
+
+
+    public BallStatus playBall(Ball ball) {
+        if(this.equals(ball)) return BallStatus.STRIKE;
+        if(matchBallNum(ball.ballNum)) return BallStatus.BALL;
+        return BallStatus.NOTHING;
+    }
+
+    private boolean matchBallNum(int ballNum) {
+        return this.ballNum == ballNum;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if(this == o)return true;
+        if(o == null || this.getClass() != o.getClass()) return false; // 실행 중인 클래스 객체의 정보를 확인
+        Ball ball = (Ball) o;
+        return position == ball.position &&
+                ballNum == ball.ballNum;
+    }
+
+
+}
diff --git a/src/main/java/baseball/BallStatus.java b/src/main/java/baseball/BallStatus.java
new file mode 100644
index 000000000..4e99126a6
--- /dev/null
+++ b/src/main/java/baseball/BallStatus.java
@@ -0,0 +1,15 @@
+package baseball;
+
+public enum BallStatus {
+    NOTHING, STRIKE, BALL;
+
+    public boolean isNotNothing() {
+        return this != NOTHING;
+    }
+    public boolean isStrike() {
+        return this == STRIKE;
+    }
+    public boolean isBall() {
+        return this == BALL;
+    }
+}
diff --git a/src/main/java/baseball/Balls.java b/src/main/java/baseball/Balls.java
new file mode 100644
index 000000000..b3cb0c5b1
--- /dev/null
+++ b/src/main/java/baseball/Balls.java
@@ -0,0 +1,39 @@
+package baseball;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Balls {
+    private final List<Ball> balls; // computer balls
+
+    public Balls(List<Integer> computer) {
+        this.balls = getBalls(computer);
+    }
+
+
+    private static List<Ball> getBalls(List<Integer> computer) {
+        List<Ball> balls = new ArrayList<>();
+        for (int i = 0; i < 3; i++) {
+            balls.add(new Ball(i+1, computer.get(i)));
+        }
+        return balls;
+    }
+    public Score play(List<Integer> userInput) {
+        Balls userBalls = new Balls(userInput);
+        Score result = new Score();
+        // 비교 분석
+        for(Ball answer : balls){ // computerBall
+            BallStatus status = userBalls.playBalls(answer); // 앞 뒤에 들어갈 객체가 바뀌어도 strike,ball 판별에는 문제가 되지 않음
+            result.report(status);
+        }
+        return result;
+    }
+
+    public BallStatus playBalls(Ball userBall) {
+        return balls.stream()
+                .map(answer -> answer.playBall(userBall))
+                .filter(BallStatus::isNotNothing)
+                .findFirst()
+                .orElse(BallStatus.NOTHING);
+    }
+}
diff --git a/src/main/java/baseball/BallsNumber.java b/src/main/java/baseball/BallsNumber.java
new file mode 100644
index 000000000..5a5e4b4ee
--- /dev/null
+++ b/src/main/java/baseball/BallsNumber.java
@@ -0,0 +1,48 @@
+package baseball;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class BallsNumber {
+
+    public List<Integer> splitNumber(int userNumber) {
+        List<Integer> userNumList = new ArrayList<>();
+
+        while(userNumber > 0) {
+            userNumList.add(0, userNumber % 10);
+            userNumber /= 10;
+        }
+
+        return userNumList;
+    }
+    public static boolean validateNumber(List<Integer> ballNumbers) {
+        return areAllNumbersValid(ballNumbers) && areAllNumbersUnique(ballNumbers);
+    }
+
+    // 1~9사이 숫자인지 확인
+
+    private static boolean areAllNumbersValid(List<Integer> ballNumbers) {
+        return ballNumbers.stream().allMatch(BallsNumber::isValidNumber);
+    }
+    private static boolean isValidNumber(int x) {
+        if (!(0 < x && x < 10)) {
+            System.out.println("1~9 사이 숫자로 이루어진 수를 입력해주세요.");
+            return false;
+        }
+        return true;
+    }
+    // 숫자 중복 확인
+    private static boolean areAllNumbersUnique(List<Integer> ballNumbers) {
+        return ballNumbers.stream().allMatch(x -> isUniqueNumber(ballNumbers, x));
+    }
+    private static boolean isUniqueNumber(List<Integer> ballNumbers, int x) {
+        if (!(Collections.frequency(ballNumbers, x) == 1)) {
+            System.out.println("중복 숫자가 없는 수를 입력해주세요.");
+            return false;
+        }
+        return true;
+
+    }
+}
+
diff --git a/src/main/java/baseball/BaseBall.java b/src/main/java/baseball/BaseBall.java
new file mode 100644
index 000000000..457262aed
--- /dev/null
+++ b/src/main/java/baseball/BaseBall.java
@@ -0,0 +1,46 @@
+package baseball;
+
+import ui.InputView;
+import ui.ResultView;
+import utils.MakeRandomNum;
+
+import java.util.List;
+import java.util.Scanner;
+
+import static baseball.BallsNumber.validateNumber;
+
+public class BaseBall {
+    public void game(){
+        // computer num
+        MakeRandomNum randomNum = new MakeRandomNum();
+        Balls answer = new Balls(randomNum.makeRandomNum());
+
+        // user num
+        Scanner sc = new Scanner(System.in);
+        int strike = 0;
+
+        while(strike != 3) {
+            System.out.print("숫자를 입력해 주세요 : ");
+            int userInput = sc.nextInt();
+
+            // 유효성 검사
+            BallsNumber ball = new BallsNumber();
+
+            List<Integer> ballList = ball.splitNumber(userInput);
+            if(!validateNumber(ballList)) continue;
+
+            strike = ResultView.result(answer.play(ballList));
+        }
+
+    }
+    public BaseBall() {
+        while(true){
+            game();
+            if(InputView.inputNumber()!=1) return;
+        }
+    }
+
+    public static void main(String[] args) {
+        new BaseBall();
+    }
+}
diff --git a/src/main/java/baseball/Score.java b/src/main/java/baseball/Score.java
new file mode 100644
index 000000000..aac8c2ebe
--- /dev/null
+++ b/src/main/java/baseball/Score.java
@@ -0,0 +1,26 @@
+package baseball;
+
+public class Score {
+    private int strike = 0;
+    private int ball = 0;
+
+
+    public int getStrike() {
+        return this.strike;
+    }
+    public int getBall() {
+        return this.ball;
+    }
+
+    public void report(BallStatus status) {
+        if(status.isBall()) this.ball += 1;
+        if(status.isStrike()) this.strike += 1;
+
+    }
+    public boolean isGameEnd() {
+        return strike == 3;
+    }
+    public boolean isNothing() {
+        return this.strike == 0 && this.ball == 0;
+    }
+}
diff --git a/src/main/java/ui/InputView.java b/src/main/java/ui/InputView.java
new file mode 100644
index 000000000..599eab35e
--- /dev/null
+++ b/src/main/java/ui/InputView.java
@@ -0,0 +1,12 @@
+package ui;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+
+public class InputView {
+    public static int inputNumber() {
+        Scanner sc = new Scanner(System.in);
+        return sc.nextInt();
+    }
+}
diff --git a/src/main/java/ui/ResultView.java b/src/main/java/ui/ResultView.java
new file mode 100644
index 000000000..54e1b3d96
--- /dev/null
+++ b/src/main/java/ui/ResultView.java
@@ -0,0 +1,29 @@
+package ui;
+
+import baseball.Score;
+
+public class ResultView {
+    public static int result(Score score) {
+        StringBuilder sb = new StringBuilder();
+        int result = 0;
+
+        if(score.isNothing()) {
+            sb.append("낫싱");
+        }
+        if(score.getBall() > 0) {
+            sb.append(score.getBall()).append("볼 ");
+        }
+        if(score.getStrike() > 0){
+            sb.append(score.getStrike()).append("스트라이크");
+            result = score.getStrike();
+        }
+        if(score.isGameEnd()) {
+            sb.append("\n")
+                    .append("3개의 숫자를 모두 맞히셨습니다! 게임 종료").append("\n")
+                    .append("게임을 새로 시작하려면 1, 종료하려면 2를 입력하세요.");
+        }
+        System.out.println(sb);
+
+        return result;
+    }
+}
diff --git a/src/main/java/utils/MakeRandomNum.java b/src/main/java/utils/MakeRandomNum.java
new file mode 100644
index 000000000..c9721c0af
--- /dev/null
+++ b/src/main/java/utils/MakeRandomNum.java
@@ -0,0 +1,31 @@
+package utils;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+public class MakeRandomNum {
+    private List<Integer> numList;
+    private static boolean[] check; // true이면 값이 들어가있다
+    public MakeRandomNum() {
+        check = new boolean[10]; // 1~9 사이의 수 파악
+    }
+    public List<Integer> makeRandomNum(){
+        numList = new ArrayList<>();
+        Random random = new Random();
+        int idx = 0;
+        while(idx != 3) {
+            int num = random.nextInt(9)+1; // 1 ~ 4 까지의 무작위 int 값 리턴
+            idx = checkDuplicate(idx, num);
+        }
+        return numList;
+    }
+    public int checkDuplicate(int idx, int num) {
+        if(!check[num]) {
+            idx++;
+            check[num] = true;
+            numList.add(num);
+        }
+        return idx;
+    }
+}
diff --git a/src/test/java/baseball/BallTest.java b/src/test/java/baseball/BallTest.java
new file mode 100644
index 000000000..fc4d5fef2
--- /dev/null
+++ b/src/test/java/baseball/BallTest.java
@@ -0,0 +1,29 @@
+package baseball;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class BallTest {
+    // Step 1.
+    @Test
+    @DisplayName("userball과 computerball 각각 1개씩 비교 - strike")
+    void strike() {
+        Ball computerBall = new Ball(1, 5);
+
+        assertThat(computerBall.playBall(new Ball(1, 5))).isEqualTo(BallStatus.STRIKE);
+    }
+    @Test
+    @DisplayName("userball과 computerball 각각 1개씩 비교 - ball")
+    void ball() {
+        Ball computerBall = new Ball(1, 5);
+        assertThat(computerBall.playBall(new Ball(2, 5))).isEqualTo(BallStatus.BALL);
+    }
+    @Test
+    @DisplayName("userball과 computerball 각각 1개씩 비교 - nothing")
+    void nothing() {
+        Ball computerBall = new Ball(1, 5);
+        assertThat(computerBall.playBall(new Ball(2, 6))).isEqualTo(BallStatus.NOTHING);
+    }
+}
diff --git a/src/test/java/baseball/BallsTest.java b/src/test/java/baseball/BallsTest.java
new file mode 100644
index 000000000..0f51b5d69
--- /dev/null
+++ b/src/test/java/baseball/BallsTest.java
@@ -0,0 +1,82 @@
+package baseball;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.util.Arrays;
+import java.util.List;
+
+import static baseball.BallsNumber.validateNumber;
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class BallsTest {
+
+    @Test
+    @DisplayName("user Ball의 유효성 검사- success")
+    void validate_success() {
+        assertThat(validateNumber(Arrays.asList(1,2,3))).isTrue();
+    }
+    @Test
+    @DisplayName("user Ball의 유효성 검사 - 중복 검사")
+    void validate_fail1() {
+        assertThat(validateNumber(Arrays.asList(1,2,2))).isFalse();
+
+    }@Test
+    @DisplayName("user Ball의 유효성 검사 - 1~9사이 숫자")
+    void validate_fail2() {
+        assertThat(validateNumber(Arrays.asList(1,2,0))).isFalse();
+
+    }
+
+    // step 3.
+    @Test
+    @DisplayName("userball 3개와 computerball 3개를 가지고 비교 - strike")
+    void play_3strike() {
+        Balls computer = new Balls(Arrays.asList(1,2,3));
+        Score result = computer.play(Arrays.asList(1,2,3));
+        assertThat(result.getStrike()).isEqualTo(3);
+        assertThat(result.getBall()).isEqualTo(0);
+        assertThat(result.isGameEnd()).isTrue();
+    }
+    @Test
+    @DisplayName("userball 3개와 computerball 3개를 가지고 비교 - ball")
+    void play_1strike_2ball() {
+        Balls computer = new Balls(Arrays.asList(1,2,3));
+        Score result = computer.play(Arrays.asList(1,3,2));
+        assertThat(result.getStrike()).isEqualTo(1);
+        assertThat(result.getBall()).isEqualTo(2);
+    }
+
+    @Test
+    @DisplayName("userball 3개와 computerball 3개를 가지고 비교 - ball")
+    void play_nothing() {
+        Balls computer = new Balls(Arrays.asList(1,2,3));
+        Score result = computer.play(Arrays.asList(4,5,6));
+        assertThat(result.getStrike()).isNotEqualTo(1);
+        assertThat(result.getBall()).isNotEqualTo(2);
+        assertThat(result.isNothing()).isTrue();
+    }
+    // Step 2.
+    @Test
+    @DisplayName("userball 1개와 computerball 리스트를 가지고 비교 - strike")
+    void strike() {
+        Balls computerBall = new Balls(Arrays.asList(1, 2, 3));
+        assertThat(computerBall.playBalls(new Ball(1, 1))).isEqualTo(BallStatus.STRIKE);
+
+    }
+    @Test
+    @DisplayName("userball 1개와 computerball 리스트를 가지고 비교 - ball")
+    void ball() {
+        Balls computerBall = new Balls(Arrays.asList(1, 2, 3));
+        assertThat(computerBall.playBalls(new Ball(1, 3))).isEqualTo(BallStatus.BALL);
+
+    }
+    @Test
+    @DisplayName("userball 1개와 computerball 리스트를 가지고 비교 - nothing")
+    void nothing() {
+        Balls computerBall = new Balls(Arrays.asList(1, 2, 3));
+        assertThat(computerBall.playBalls(new Ball(1, 4))).isEqualTo(BallStatus.NOTHING);
+
+    }
+}