diff --git a/README.md b/README.md
index fcf3f057..72fa4561 100644
--- a/README.md
+++ b/README.md
@@ -5,3 +5,15 @@
 
 ## 과제 제출 과정
 * [과제 제출 방법](https://github.com/next-step/nextstep-docs/tree/master/ent-precourse)
+
+## 기능 요구사항
+- [x] 3자리 수를 0~9 숫자 3개로 변환
+- [x] 1~9의 서로 다른 임의의 숫자 3개 생성
+- [x] 스트라이크 / 볼 / 낫싱 판별
+- [x] 메인 로직 - 게임 종료 조건 만족할 때까지 게임 반복
+
+## 테스트 코드 작성
+해결할 점: private 변수에 접근할 수 없어 테스트 불가
+- [x] 3자리 수를 자릿수로 split
+- [x] 랜덤 숫자 3개 생성
+- [x] 스트라이크 / 볼 / 낫싱 판별
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diff --git a/src/main/java/Game.java b/src/main/java/Game.java
new file mode 100644
index 00000000..616fc09f
--- /dev/null
+++ b/src/main/java/Game.java
@@ -0,0 +1,36 @@
+import java.util.Scanner;
+
+public class Game {
+    private NumSet answer;
+
+    public void reset() {
+        answer = new NumSet();
+    }
+
+    public void start() {
+        Scanner sc = new Scanner(System.in);
+        boolean isCorrect = false;
+        while (!isCorrect) {
+            System.out.print("숫자를 입력해주세요 : ");
+            int[] submitted = NumSet.convertToList(sc.nextInt());
+
+            MatchResult matchResult = answer.match(submitted);
+            matchResult.printResult();
+
+            isCorrect = matchResult.isCorrect();
+        }
+        System.out.println("3개의 숫자를 모두 맞히셨습니다! 게임 종료");
+    }
+
+    public boolean willContinue() {
+        Scanner sc = new Scanner(System.in);
+
+        int next = 0;
+        while (next != 1 && next != 2) {
+            System.out.println("게임을 새로 시작하려면 1, 종료하려면 2를 입력하세요.");
+            next = sc.nextInt();
+        }
+
+        return next == 1;
+    }
+}
diff --git a/src/main/java/Main.java b/src/main/java/Main.java
new file mode 100644
index 00000000..01c3d2d9
--- /dev/null
+++ b/src/main/java/Main.java
@@ -0,0 +1,11 @@
+public class Main {
+    public static void main(String[] args) {
+        Game game = new Game();
+        boolean willContinue = true;
+        while (willContinue) {
+            game.reset();
+            game.start();
+            willContinue = game.willContinue();
+        }
+    }
+}
diff --git a/src/main/java/MatchResult.java b/src/main/java/MatchResult.java
new file mode 100644
index 00000000..5d0a9b92
--- /dev/null
+++ b/src/main/java/MatchResult.java
@@ -0,0 +1,22 @@
+public class MatchResult {
+    private int strike, ball;
+
+    public MatchResult(int strike, int ball) {
+        this.strike = strike;
+        this.ball = ball;
+    }
+
+    public boolean isCorrect() {
+        return strike == 3;
+    }
+
+    public void printResult() {
+        if (strike != 0)
+            System.out.print(strike + " 스트라이크 ");
+        if (ball != 0)
+            System.out.print(ball + "볼");
+        if (strike == 0 && ball == 0)
+            System.out.print("낫싱");
+        System.out.println();
+    }
+}
diff --git a/src/main/java/NumSet.java b/src/main/java/NumSet.java
new file mode 100644
index 00000000..15b44e90
--- /dev/null
+++ b/src/main/java/NumSet.java
@@ -0,0 +1,64 @@
+import java.util.Random;
+
+public class NumSet {
+    private int[] numArr = new int[3];
+
+    public NumSet() {
+        for (int i = 0; i < 3; i++)
+            setRandomNum(i);
+    }
+
+    private void setRandomNum(int idx) {
+        Random random = new Random();
+        boolean isDiff = false;
+        while (!isDiff) {
+            numArr[idx] = random.nextInt(1, 10);
+            isDiff = isDiffFromForward(idx);
+        }
+    }
+
+    private boolean isDiffFromForward(int idx) {
+        boolean isPrevDiff = true;
+        for (int i = 0; i < idx; i++)
+            isPrevDiff = isPrevDiff && (numArr[idx] != numArr[i]);
+        return isPrevDiff;
+    }
+
+    // 사용자가 '112'처럼 중복 숫자를 입력할 때
+    // 스트라이크와 볼이 중복 카운트되지 않도록
+    // 포함하는 수 카운트에서 스트라이크를 빼서 볼을 계산
+    public MatchResult match(int[] userArr) {
+        int strike = countStrike(userArr);
+        int ball = countContains(userArr) - strike;
+        return new MatchResult(strike, ball);
+    }
+
+    private int countStrike(int[] userArr) {
+        int strike = 0;
+        for (int i = 0; i < 3; i++)
+            strike += (numArr[i] == userArr[i]) ? 1 : 0;    // depth 1로 만들기 위해...
+        return strike;
+    }
+
+    private int countContains(int[] userArr) {
+        int cnt = 0;
+        for (int i = 0; i < 3; i++)
+            cnt += contains(i, userArr) ? 1 : 0;
+        return cnt;
+    }
+
+    private boolean contains(int idx, int[] userArr) {
+        boolean hasNum = false;
+        for (int i = 0; i < 3; i++)
+            hasNum = hasNum || (numArr[idx] == userArr[i]);
+        return hasNum;
+    }
+
+    public static int[] convertToList(int num) {
+        return new int[]{
+                num / 100,
+                num / 10 % 10,
+                num % 10
+        };
+    }
+}
diff --git a/src/test/java/NumSetTest.java b/src/test/java/NumSetTest.java
new file mode 100644
index 00000000..2f7407f5
--- /dev/null
+++ b/src/test/java/NumSetTest.java
@@ -0,0 +1,58 @@
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+import java.lang.reflect.Field;
+
+import static org.assertj.core.api.Assertions.*;
+
+class NumSetTest {
+    @Test
+    void convertToList() {
+        assertThat(NumSet.convertToList(123)).isEqualTo(new int[]{1, 2, 3});
+        assertThat(NumSet.convertToList(719)).isEqualTo(new int[]{7, 1, 9});
+    }
+
+    @Test
+    void generateRandom3Number() throws NoSuchFieldException, IllegalAccessException {
+        Field numArrField = NumSet.class.getDeclaredField("numArr");
+        numArrField.setAccessible(true);
+
+        for (int i = 0; i < 200; i++) {
+            NumSet numSet = new NumSet();
+            int[] numArr = (int[]) numArrField.get(numSet);
+
+            assertThat(numArr[0]).isBetween(1, 9);
+            assertThat(numArr[1]).isBetween(1, 9);
+            assertThat(numArr[2]).isBetween(1, 9);
+
+            assertThat(numArr[0]).isNotEqualTo(numArr[1]);
+            assertThat(numArr[1]).isNotEqualTo(numArr[2]);
+            assertThat(numArr[2]).isNotEqualTo(numArr[0]);
+        }
+    }
+
+
+    @ParameterizedTest
+    @CsvSource({"1,2,3,3,0", "1,3,2,1,2", "1,2,4,2,0", "4,5,1,0,1", "4,5,6,0,0"})
+    void match(int userNum1, int userNum2, int userNum3, int strikeExpected, int ballExpected) throws NoSuchFieldException, IllegalAccessException {
+        Field numArrField = NumSet.class.getDeclaredField("numArr");
+        numArrField.setAccessible(true);
+
+        NumSet numSet = new NumSet();
+        numArrField.set(numSet, new int[]{1, 2, 3});
+
+        Field strikeField = MatchResult.class.getDeclaredField("strike");
+        strikeField.setAccessible(true);
+
+        Field ballField = MatchResult.class.getDeclaredField("ball");
+        ballField.setAccessible(true);
+
+        MatchResult matchResult = numSet.match(new int[]{userNum1, userNum2, userNum3});
+        int strike = strikeField.getInt(matchResult);
+        int ball = ballField.getInt(matchResult);
+
+        assertThat(strike).isEqualTo(strikeExpected);
+        assertThat(ball).isEqualTo(ballExpected);
+    }
+}
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