diff --git a/src/main/java/com/ohgiraffers/level01/basic/Application.java b/src/main/java/com/ohgiraffers/level01/basic/Application.java
new file mode 100644
index 0000000..31ea4ad
--- /dev/null
+++ b/src/main/java/com/ohgiraffers/level01/basic/Application.java
@@ -0,0 +1,13 @@
+package com.ohgiraffers.level01.basic;
+
+public class Application {
+    public static void main(String[] args){
+        Calculator cal = new Calculator();
+
+        cal.checkMethod();
+        System.out.println("1부터 10까지의 합 : " + cal.sum1to10());
+        cal.checkMaxNumber(10, 20);
+        System.out.println("10과 20의 합은 : " + cal.sumTwoNumber(10,20));
+        System.out.println("10과 5의 차는 : " + cal.minusTwoNumber(10,5));
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/com/ohgiraffers/level01/basic/Calculator.java b/src/main/java/com/ohgiraffers/level01/basic/Calculator.java
new file mode 100644
index 0000000..825c801
--- /dev/null
+++ b/src/main/java/com/ohgiraffers/level01/basic/Calculator.java
@@ -0,0 +1,29 @@
+package com.ohgiraffers.level01.basic;
+
+public class Calculator {
+    public void checkMethod(){
+        System.out.println("메소드 호출 확인");
+    }
+    public int sum1to10(){
+        int a = 0;
+        for(int i = 1; i <= 10; i++){
+            a = a + i;
+        }
+        return a;
+    }
+    public void checkMaxNumber(int a, int b){
+        int max = a;
+        if(b > a) {
+            max = b;
+        }
+        System.out.println("두 수 중 큰 수는 " + max + "이다.");
+    }
+    public int sumTwoNumber(int a, int b){
+        int sum = a + b;
+        return sum;
+    }
+    public int minusTwoNumber(int a, int b){
+        int minus = a - b;
+        return minus;
+    }
+}
diff --git a/src/main/java/com/ohgiraffers/level02/normal/Application.java b/src/main/java/com/ohgiraffers/level02/normal/Application.java
new file mode 100644
index 0000000..d093f71
--- /dev/null
+++ b/src/main/java/com/ohgiraffers/level02/normal/Application.java
@@ -0,0 +1,10 @@
+package com.ohgiraffers.level02.normal;
+
+public class Application {
+    public static void main(String[] args){
+        System.out.println(RandomMaker.randomNumber(-50, 50));
+        System.out.println(RandomMaker.randomUpperAlpabet(10));
+        System.out.println(RandomMaker.rockPaperScissors());
+        System.out.println(RandomMaker.tossCoin());
+    }
+}
diff --git a/src/main/java/com/ohgiraffers/level02/normal/RandomMaker.java b/src/main/java/com/ohgiraffers/level02/normal/RandomMaker.java
new file mode 100644
index 0000000..958efd8
--- /dev/null
+++ b/src/main/java/com/ohgiraffers/level02/normal/RandomMaker.java
@@ -0,0 +1,37 @@
+package com.ohgiraffers.level02.normal;
+
+public class RandomMaker {
+    public static int randomNumber(int min, int max){
+        int random = (int)(Math.random() * (max-min)) + min;
+        return random;
+    }
+    public static String randomUpperAlpabet(int length){
+        char [] arr = new char[10];
+        for(int i = 0; i< arr.length; i++) {
+            arr[i] = (char)(Math.random()*26 + 'A');
+        }
+        return new String(arr);
+    }
+    public static String rockPaperScissors(){
+        int x = (int)(Math.random()*3);
+        String str = " ";
+        if(x==0){
+            str = "가위";
+        }else if(x==1){
+            str = "바위";
+        }else if(x==2){
+            str = "보";
+        }
+        return str;
+    }
+    public static String tossCoin(){
+        int x = (int)(Math.random()*2);
+        String str = " ";
+        if(x==0) {
+            str = "앞면";
+        }else{
+            str = "뒷면";
+        }
+        return str;
+    }
+}