diff --git a/src/practice02/Prob01.java b/src/practice02/Prob01.java
index 8dbc760..a640b3a 100644
--- a/src/practice02/Prob01.java
+++ b/src/practice02/Prob01.java
@@ -1,9 +1,27 @@
 package practice02;
 
+import java.util.Scanner;
+
 public class Prob01 {
 
 	public static void main(String[] args) {
 		final int[] MONEYS = { 50000, 10000, 5000, 1000, 500, 100, 50, 10, 5, 1 };
+
+		System.out.print("금액 : ");
+		Scanner scanner = new Scanner(System.in);
+		int money = scanner.nextInt();
+		
+		for(int i=0;i<MONEYS.length;i++) {
+			int num =0;
+			num = money/MONEYS[i];
+			if(money/MONEYS[i]!=0) {
+				money -= MONEYS[i]*num;
+				System.out.println(MONEYS[i]+"원 : "+num+"개");
+			}
+			else {
+				System.out.println(MONEYS[i]+"원 : "+num+"개");
+			}
+		}
 	}
 
 }
diff --git a/src/practice02/Prob02.java b/src/practice02/Prob02.java
index 83548be..44c82d9 100644
--- a/src/practice02/Prob02.java
+++ b/src/practice02/Prob02.java
@@ -1,8 +1,22 @@
 package practice02;
 
+import java.util.Scanner;
+
 public class Prob02 {
 
 	public static void main(String[] args) {
+		Scanner in = new Scanner(System.in);
+		int intArray[] = new int[5];
+		double sum = 0;
+		
+		System.out.println("5개의 숫자를 입력하세요.");
+		
+		for(int i=0;i<intArray.length;i++) {
+			intArray[i] = in.nextInt();
+			sum += intArray[i];
+		}
+		System.out.println("평균은 "+sum/intArray.length+" 입니다.");
+		
 	}
 
 }
diff --git a/src/practice02/Prob03.java b/src/practice02/Prob03.java
index c56a9e4..1d035b9 100644
--- a/src/practice02/Prob03.java
+++ b/src/practice02/Prob03.java
@@ -15,4 +15,17 @@ public static void main(String args[]) {
 		printCharArray(c);
 	}
 	
+	public static void replaceSpace(char a[]) {
+		for(int i=0;i<a.length;i++) {
+			if(a[i]==' ') {//spacebar ASCII CODE :32
+				a[i]=',';//, ASCII CODE :44
+			}
+		}
+	}
+	
+	public static void printCharArray(char[] a) {
+		System.out.println(a);
+		
+	}
+	
 }
diff --git a/src/practice02/Prob04.java b/src/practice02/Prob04.java
index 4e36d34..7532a03 100644
--- a/src/practice02/Prob04.java
+++ b/src/practice02/Prob04.java
@@ -12,9 +12,16 @@ public static void main(String[] args) {
 	
 	public static char[] reverse(String str) {
 		/* 코드를 완성합니다 */
+		String reverseStr = (new StringBuffer(str)).reverse().toString();
+		char[] c = new char[reverseStr.length()];
+		for(int i =0;i<str.length();i++) {
+			c[i] = reverseStr.charAt(i);
+		}
+		return c;
 	}
 
 	public static void printCharArray(char[] array){
 		/* 코드를 완성합니다 */
+		System.out.println(array);
 	}
 }
diff --git a/src/practice02/Prob05.java b/src/practice02/Prob05.java
index 0e54b0f..96d62c7 100644
--- a/src/practice02/Prob05.java
+++ b/src/practice02/Prob05.java
@@ -1,10 +1,51 @@
 package practice02;
 
-public class Prob05 {
+import java.util.Random;
+import java.util.Scanner;
 
+public class Prob05 {
 
 	public static void main(String[] args) {
 
-	}
+		while(true) {
+			Random random = new Random();
+			int num = random.nextInt(100)+1;
+			int checkNum = 0;
+			int start = 1;
+			int end = 100;
+
+			System.out.println("수를 결정하였습니다. 맞추어보세요\n"+start+"-"+end);
+
+			Scanner scanner = new Scanner(System.in);
+
+			while(true) {
+				checkNum++;
+				System.out.print(checkNum+">>");
+				int a = scanner.nextInt();
+
+				if(num>a) {
+
+					start = a;
+					System.out.println("더 높게\n"+a+"-"+end);
+				} else if(num<a){
 
+					end = a;
+					System.out.println("더 낮게\n"+start+"-"+a);
+				} else {
+
+					System.out.print("맞았습니다.\n다시하시겠습니까(y/n)>>");
+					break;
+
+				}
+			}
+			String answer = scanner.next();
+			if(answer.equals("n")) {
+				break;
+			} 
+		}
+
+
+	}
 }
+
+