diff --git a/README.md b/README.md
index fcf3f057..33d893c7 100644
--- a/README.md
+++ b/README.md
@@ -5,3 +5,14 @@
 
 ## 과제 제출 과정
 * [과제 제출 방법](https://github.com/next-step/nextstep-docs/tree/master/ent-precourse)
+
+## 구현할 기능 목록
+* 게임을 진행할 메소드 정의
+* 변수 초기화 하기
+* 컴퓨터의 숫자 정하기
+* 컴퓨터의 숫자 카운트하기(어떤 숫자가 등장했는지)
+* 숫자 입력받기
+* 결과 구하기
+* 결과 출력하기
+* 계속할지 여부 묻기
+* 테스트 코드 작성하기
\ No newline at end of file
diff --git a/src/main/java/NumberBaseball.java b/src/main/java/NumberBaseball.java
new file mode 100644
index 00000000..1fa298c7
--- /dev/null
+++ b/src/main/java/NumberBaseball.java
@@ -0,0 +1,119 @@
+import java.util.Collections;
+import java.util.List;
+import java.util.Scanner;
+import java.util.Arrays;
+
+public class NumberBaseball {
+    final int NUMBER_COUNT = 3;
+    final int MAX_NUM = 9;
+    final int MIN_NUM = 1;
+    final int CONTINUE = 1;
+    final int END = 2;
+    int[] random_numbers = new int[NUMBER_COUNT];
+    boolean[] random_numbers_count = new boolean[MAX_NUM + 1];
+    int[] input_numbers = new int[NUMBER_COUNT];
+    int strike;
+    int ball;
+
+    public void initialize_parameter(){
+        Arrays.fill(random_numbers, 0);
+        Arrays.fill(random_numbers_count, false);
+        Arrays.fill(input_numbers, 0);
+        strike = 0;
+        ball = 0;
+    }
+
+    public void generate_random_numbers() {
+        Integer[] numbers = new Integer[MAX_NUM + 1];
+        Arrays.setAll(numbers, i -> i + 1);
+        List<Integer> numberList = Arrays.asList(numbers);
+        Collections.shuffle(numberList);
+        for(int i = 0; i < NUMBER_COUNT; ++i){
+            random_numbers[i] = numberList.get(i);
+        }
+    }
+
+    public void get_input_numbers() {
+        System.out.print("숫자를 입력해주세요 : ");
+        Scanner scanner = new Scanner(System.in);
+        String input = scanner.nextLine();
+        for(int i = 0; i < NUMBER_COUNT; ++i){
+            input_numbers[i] = input.charAt(i) - '0';
+        }
+    }
+
+    public void get_random_numbers_count() {
+        for(int i = 0; i < NUMBER_COUNT; ++i){
+            random_numbers_count[random_numbers[i]] = true;
+        }
+    }
+
+    public void count_strike_or_ball(int idx) {
+        if(random_numbers[idx] == input_numbers[idx]){
+            ++strike;
+            return;
+        }
+        if(random_numbers_count[input_numbers[idx]]){
+            ++ball;
+        }
+    }
+
+    public void get_game_result() {
+        strike = 0;
+        ball = 0;
+        for(int i = 0; i < NUMBER_COUNT; ++i) {
+            count_strike_or_ball(i);
+        }
+    }
+
+    public void print_game_result() {
+        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.print("\n");
+    }
+
+    public boolean continue_or_end(int input){
+        if (input == CONTINUE){
+            return true;
+        }
+        if (input == END){
+            return false;
+        }
+        return false;
+    }
+
+    public boolean print_end_message(){
+        System.out.println("3개의 숫자를 모두 맞히셨습니다! 게임 종료");
+        System.out.println("게임을 새로 시작하려면 1, 종료하려면 2를 입력하세요");
+        Scanner scanner = new Scanner(System.in);
+        int input = Integer.parseInt(scanner.nextLine());
+        return continue_or_end(input);
+    }
+
+    public boolean do_game() {
+        initialize_parameter();
+        generate_random_numbers();
+        get_random_numbers_count();
+        while(strike != NUMBER_COUNT) {
+            get_input_numbers();
+            get_game_result();
+            print_game_result();
+        }
+        return print_end_message();
+    }
+
+    public static void main(String[] args) {
+        NumberBaseball numberBaseball = new NumberBaseball();
+        boolean game_continue = true;
+        while(game_continue){
+            game_continue = numberBaseball.do_game();
+        }
+    }
+}
diff --git a/src/test/java/NumberBaseballTest.java b/src/test/java/NumberBaseballTest.java
new file mode 100644
index 00000000..b679c7e9
--- /dev/null
+++ b/src/test/java/NumberBaseballTest.java
@@ -0,0 +1,103 @@
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class NumberBaseballTest {
+    NumberBaseball numberBaseball = new NumberBaseball();
+
+    void set_random_numbers() {
+        numberBaseball.random_numbers[0] = 7;
+        numberBaseball.random_numbers[1] = 1;
+        numberBaseball.random_numbers[2] = 3;
+    }
+
+    void set_random_numbers_count() {
+        numberBaseball.random_numbers_count[1] = true;
+        numberBaseball.random_numbers_count[3] = true;
+        numberBaseball.random_numbers_count[7] = true;
+    }
+
+
+    void set_input_numbers_same() {
+        numberBaseball.input_numbers[0] = 7;
+        numberBaseball.input_numbers[1] = 1;
+        numberBaseball.input_numbers[2] = 3;
+    }
+
+    @Test
+    void initialize_parameter_test() {
+        numberBaseball.initialize_parameter();
+        assertThat(numberBaseball.random_numbers).containsOnly(0, 0, 0);
+        assertThat(numberBaseball.random_numbers_count).contains(false);
+        assertThat(numberBaseball.input_numbers).containsOnly(0, 0, 0);
+        assertThat(numberBaseball.strike).isEqualTo(0);
+        assertThat(numberBaseball.ball).isEqualTo(0);
+    }
+
+    @ParameterizedTest
+    @ValueSource(ints = {0, 1, 2})
+    void generate_random_numbers_test(int idx) {
+        numberBaseball.generate_random_numbers();
+        assertThat(numberBaseball.random_numbers[idx]).
+                isGreaterThanOrEqualTo(numberBaseball.MIN_NUM);
+        assertThat(numberBaseball.random_numbers[idx]).
+                isLessThanOrEqualTo(numberBaseball.MAX_NUM);
+    }
+
+
+    @Test
+    void get_random_numbers_count() {
+        set_random_numbers();
+        numberBaseball.get_random_numbers_count();
+        assertThat(numberBaseball.random_numbers_count[1]).isEqualTo(true);
+        assertThat(numberBaseball.random_numbers_count[3]).isEqualTo(true);
+        assertThat(numberBaseball.random_numbers_count[7]).isEqualTo(true);
+    }
+
+    @Test
+    void count_strike_test() {
+        set_random_numbers();
+        set_random_numbers_count();
+        numberBaseball.input_numbers[0] = 7;
+        numberBaseball.count_strike_or_ball(0);
+        assertThat(numberBaseball.strike).isEqualTo(1);
+        assertThat(numberBaseball.ball).isEqualTo(0);
+    }
+
+    @Test
+    void count_ball_test() {
+        set_random_numbers();
+        set_random_numbers_count();
+        numberBaseball.input_numbers[0] = 1;
+        numberBaseball.count_strike_or_ball(0);
+        assertThat(numberBaseball.strike).isEqualTo(0);
+        assertThat(numberBaseball.ball).isEqualTo(1);
+    }
+
+    @Test
+    void count_nothing_test() {
+        set_random_numbers();
+        set_random_numbers_count();
+        numberBaseball.input_numbers[0] = 2;
+        numberBaseball.count_strike_or_ball(0);
+        assertThat(numberBaseball.strike).isEqualTo(0);
+        assertThat(numberBaseball.ball).isEqualTo(0);
+    }
+
+    @Test
+    void get_game_result_test() {
+        set_random_numbers();
+        set_input_numbers_same();
+        numberBaseball.get_game_result();
+        assertThat(numberBaseball.strike).isEqualTo(3);
+        assertThat(numberBaseball.ball).isEqualTo(0);
+    }
+
+    @Test
+    void continue_or_end_test() {
+        assertThat(numberBaseball.continue_or_end(1)).isEqualTo(true);
+        assertThat(numberBaseball.continue_or_end(2)).isEqualTo(false);
+    }
+}
diff --git a/src/test/java/study/SetTest.java b/src/test/java/study/SetTest.java
new file mode 100644
index 00000000..df3f5141
--- /dev/null
+++ b/src/test/java/study/SetTest.java
@@ -0,0 +1,41 @@
+package study;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class SetTest {
+    private Set<Integer> numbers;
+
+    @BeforeEach
+    void setUp() {
+        numbers = new HashSet<>();
+        numbers.add(1);
+        numbers.add(2);
+        numbers.add(2);
+        numbers.add(3);
+    }
+
+    @Test
+    void test1() {
+        assertThat(numbers.size()).isEqualTo(3);
+    }
+
+    @ParameterizedTest
+    @ValueSource(ints = {1, 2, 3})
+    void test2(int number) {
+        assertThat(numbers.contains(number)).isTrue();
+    }
+
+    @ParameterizedTest
+    @CsvSource(value = {"1:true", "2:true", "3:true", "4:false", "5:false"}, delimiter = ':')
+    void test3(String number, String expected){
+        assertThat(numbers.contains(Integer.parseInt(number))).isEqualTo(expected.equals("true"));
+    }
+}
diff --git a/src/test/java/study/StringTest.java b/src/test/java/study/StringTest.java
index 43e47d90..b8358669 100644
--- a/src/test/java/study/StringTest.java
+++ b/src/test/java/study/StringTest.java
@@ -1,8 +1,10 @@
 package study;
 
+import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIndexOutOfBoundsException;
 
 public class StringTest {
     @Test
@@ -10,4 +12,35 @@ void replace() {
         String actual = "abc".replace("b", "d");
         assertThat(actual).isEqualTo("adc");
     }
+
+    @Test
+    void test1() {
+        String[] split_test1 = "1,2".split(",");
+        assertThat(split_test1).containsExactly("1","2");
+
+        String[] split_test2 = "1".split(",");
+        assertThat(split_test2).containsExactly("1");
+    }
+
+    @Test
+    void test2() {
+        String test = "(1,2)";
+        String substring_test = test.substring(1, test.length()-1);
+        assertThat(substring_test).isEqualTo("1,2");
+    }
+
+    @Test
+    void test3_1() {
+        String test = "abc";
+        assertThat(test.charAt(1)).isEqualTo('b');
+    }
+
+    @Test
+    @DisplayName("Test string charAt exception")
+    void test3_2() {
+        String test = "abc";
+        assertThatIndexOutOfBoundsException().isThrownBy(() ->{
+            test.charAt(4);
+        }).withFailMessage("Index: \\d+");
+    }
 }