diff --git a/CircleCalc.java b/CircleCalc.java
new file mode 100644
index 0000000..d93e68f
--- /dev/null
+++ b/CircleCalc.java
@@ -0,0 +1,18 @@
+import java.util.Scanner;
+
+public class CircleCalc {
+
+	public static void main(String[] args) {
+		final double PI = 3.14159;
+		double radius;
+		double area;
+
+		Scanner keyboard = new Scanner(System.in);
+		System.out.println("반지름 : ");
+		radius = keyboard.nextDouble();
+		area = PI * radius * radius;
+		System.out.println("원의 넓이 : " + area);
+
+	}
+
+}
diff --git a/FirstProgram.java b/FirstProgram.java
new file mode 100644
index 0000000..081cdff
--- /dev/null
+++ b/FirstProgram.java
@@ -0,0 +1,20 @@
+import java.util.Scanner;
+
+public class FirstProgram {
+
+	public static void main(String[] args) {
+		System.out.println("Enter two whole numbers on a line:");
+		int n1, n2;
+
+		Scanner keyboard = new Scanner(System.in);
+
+		n1 = keyboard.nextInt();
+
+		n2 = keyboard.nextInt();
+
+		System.out.println("The sum of those two number is");
+		System.out.println(n1 + n2);
+
+	}
+
+}
diff --git a/Hello.java b/Hello.java
new file mode 100644
index 0000000..d01cf13
--- /dev/null
+++ b/Hello.java
@@ -0,0 +1,10 @@
+
+public class Hello {
+
+	public static void main(String[] args) {
+		// TODO Auto-generated method stub
+		System.out.println("Hello, everyone!!");
+
+	}
+
+}
diff --git "a/[1\354\243\274\354\260\250] \352\263\274\354\240\234/Week1_1_\352\260\225\354\212\271\354\227\260.java" "b/[1\354\243\274\354\260\250] \352\263\274\354\240\234/Week1_1_\352\260\225\354\212\271\354\227\260.java"
new file mode 100644
index 0000000..b65bfeb
--- /dev/null
+++ "b/[1\354\243\274\354\260\250] \352\263\274\354\240\234/Week1_1_\352\260\225\354\212\271\354\227\260.java"	
@@ -0,0 +1,40 @@
+import java.util.Scanner;
+public class Week1_1_강승연 {
+
+	public static void main(String[] args) {
+		
+		System.out.println("============");
+		System.out.println("전공: 사이버보안");
+		System.out.println("학번: 2171056");
+		System.out.println("성명: 강승연");
+		System.out.println("============");
+		
+		//Scanner Class 선언
+		Scanner input = new Scanner(System.in); 
+		
+		//변수 선언 및 초기화
+		int base = 0;
+		int height = 0;
+		float area = 0;
+		
+		System.out.print("Input base:");
+		
+		//base 입력
+		base = input.nextInt();
+		
+		System.out.print("Input height:");
+		
+		//height 입력
+		height = input.nextInt();
+		
+		//area 계산 + 형변환
+		area = (float)(base * height) / 2;
+		
+		System.out.println("The area :" + area);
+		
+		//Scanner close
+		input.close();
+
+	}
+
+}
diff --git "a/[1\354\243\274\354\260\250] \352\263\274\354\240\234/Week1_2_\352\260\225\354\212\271\354\227\260.java" "b/[1\354\243\274\354\260\250] \352\263\274\354\240\234/Week1_2_\352\260\225\354\212\271\354\227\260.java"
new file mode 100644
index 0000000..17ba694
--- /dev/null
+++ "b/[1\354\243\274\354\260\250] \352\263\274\354\240\234/Week1_2_\352\260\225\354\212\271\354\227\260.java"	
@@ -0,0 +1,37 @@
+import java.util.Scanner;
+public class Week1_2_강승연 {
+
+	public static void main(String[] args) {
+		
+		System.out.println("============");
+		System.out.println("전공: 사이버보안");
+		System.out.println("학번: 2171056");
+		System.out.println("성명: 강승연");
+		System.out.println("============");
+		
+		//Scanner Class 선언
+		Scanner input = new Scanner(System.in);
+		
+		//변수 선언 및 초기화
+		int int1 = 0;
+		int int2 = 0;
+		int int3 = 0;
+		float avg = 0.0f;
+		
+		System.out.println("정수 세 개 입력");
+		
+		//int1,2,3 입력
+		int1 = input.nextInt();
+		int2 = input.nextInt();
+		int3 = input.nextInt();
+		
+		//avg 계산 + 형변환
+		avg = (float)(int1 + int2 + int3) / 3;
+		
+		System.out.printf("평균:" + "%.2f", avg);
+		
+		//Scanner close
+		input.close();
+	}
+
+}
diff --git "a/[1\354\243\274\354\260\250] \352\263\274\354\240\234/Week1_3_\352\260\225\354\212\271\354\227\260.java" "b/[1\354\243\274\354\260\250] \352\263\274\354\240\234/Week1_3_\352\260\225\354\212\271\354\227\260.java"
new file mode 100644
index 0000000..8842033
--- /dev/null
+++ "b/[1\354\243\274\354\260\250] \352\263\274\354\240\234/Week1_3_\352\260\225\354\212\271\354\227\260.java"	
@@ -0,0 +1,35 @@
+import java.util.Scanner;
+public class Week1_3_강승연 {
+
+	public static void main(String[] args) {
+		
+		System.out.println("============");
+		System.out.println("전공: 사이버보안");
+		System.out.println("학번: 2171056");
+		System.out.println("성명: 강승연");
+		System.out.println("============");
+		
+		//Scanner Class 선언
+		Scanner input = new Scanner(System.in);
+		
+		//변수 선언 및 초기화
+		int temF = 0;
+		float temC = 0.0f;
+		
+		//화씨온도 입력
+		System.out.print("화씨온도 입력:");
+		temF = input.nextInt();
+		
+		System.out.println("화씨온도:" + temF);
+		
+		//섭씨온도 계산 + 형변환
+		temC = (float)5/9 * (temF - 32);
+		
+		System.out.printf("섭씨온도:" + "%.1f", temC);
+		
+		//Scanner close
+		input.close();
+
+	}
+
+}