diff --git a/Git_ Exercise.xcodeproj/project.pbxproj b/Git_ Exercise.xcodeproj/project.pbxproj
index 424a5e0..945cc85 100644
--- a/Git_ Exercise.xcodeproj/project.pbxproj	
+++ b/Git_ Exercise.xcodeproj/project.pbxproj	
@@ -8,6 +8,13 @@
 
 /* Begin PBXBuildFile section */
 		2768CA08294F453B00990B98 /* main.swift in Sources */ = {isa = PBXBuildFile; fileRef = 2768CA07294F453B00990B98 /* main.swift */; };
+		90D3F153294FFCB300CEA3F8 /* Modules.swift in Sources */ = {isa = PBXBuildFile; fileRef = 90D3F152294FFCB300CEA3F8 /* Modules.swift */; };
+		90D3F156294FFFA200CEA3F8 /* AddStudent.swift in Sources */ = {isa = PBXBuildFile; fileRef = 90D3F155294FFFA200CEA3F8 /* AddStudent.swift */; };
+		90D3F15C294FFFC600CEA3F8 /* UpdateGrade.swift in Sources */ = {isa = PBXBuildFile; fileRef = 90D3F157294FFFC500CEA3F8 /* UpdateGrade.swift */; };
+		90D3F15D294FFFC600CEA3F8 /* DeleteStudent.swift in Sources */ = {isa = PBXBuildFile; fileRef = 90D3F158294FFFC500CEA3F8 /* DeleteStudent.swift */; };
+		90D3F15E294FFFC600CEA3F8 /* Exit.swift in Sources */ = {isa = PBXBuildFile; fileRef = 90D3F159294FFFC600CEA3F8 /* Exit.swift */; };
+		90D3F15F294FFFC600CEA3F8 /* RemoveGrade.swift in Sources */ = {isa = PBXBuildFile; fileRef = 90D3F15A294FFFC600CEA3F8 /* RemoveGrade.swift */; };
+		90D3F160294FFFC600CEA3F8 /* ReportCard.swift in Sources */ = {isa = PBXBuildFile; fileRef = 90D3F15B294FFFC600CEA3F8 /* ReportCard.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXCopyFilesBuildPhase section */
@@ -25,6 +32,13 @@
 /* Begin PBXFileReference section */
 		2768CA04294F453B00990B98 /* Git_ Exercise */ = {isa = PBXFileReference; explicitFileType = "compiled.mach-o.executable"; includeInIndex = 0; path = "Git_ Exercise"; sourceTree = BUILT_PRODUCTS_DIR; };
 		2768CA07294F453B00990B98 /* main.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = main.swift; sourceTree = "<group>"; };
+		90D3F152294FFCB300CEA3F8 /* Modules.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Modules.swift; sourceTree = "<group>"; };
+		90D3F155294FFFA200CEA3F8 /* AddStudent.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AddStudent.swift; sourceTree = "<group>"; };
+		90D3F157294FFFC500CEA3F8 /* UpdateGrade.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = UpdateGrade.swift; sourceTree = "<group>"; };
+		90D3F158294FFFC500CEA3F8 /* DeleteStudent.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = DeleteStudent.swift; sourceTree = "<group>"; };
+		90D3F159294FFFC600CEA3F8 /* Exit.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Exit.swift; sourceTree = "<group>"; };
+		90D3F15A294FFFC600CEA3F8 /* RemoveGrade.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = RemoveGrade.swift; sourceTree = "<group>"; };
+		90D3F15B294FFFC600CEA3F8 /* ReportCard.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ReportCard.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -57,11 +71,34 @@
 		2768CA06294F453B00990B98 /* Git_ Exercise */ = {
 			isa = PBXGroup;
 			children = (
+				90D3F154294FFF8000CEA3F8 /* Utils */,
+				90D3F151294FFCA200CEA3F8 /* Modules */,
 				2768CA07294F453B00990B98 /* main.swift */,
 			);
 			path = "Git_ Exercise";
 			sourceTree = "<group>";
 		};
+		90D3F151294FFCA200CEA3F8 /* Modules */ = {
+			isa = PBXGroup;
+			children = (
+				90D3F152294FFCB300CEA3F8 /* Modules.swift */,
+			);
+			path = Modules;
+			sourceTree = "<group>";
+		};
+		90D3F154294FFF8000CEA3F8 /* Utils */ = {
+			isa = PBXGroup;
+			children = (
+				90D3F155294FFFA200CEA3F8 /* AddStudent.swift */,
+				90D3F158294FFFC500CEA3F8 /* DeleteStudent.swift */,
+				90D3F159294FFFC600CEA3F8 /* Exit.swift */,
+				90D3F15A294FFFC600CEA3F8 /* RemoveGrade.swift */,
+				90D3F15B294FFFC600CEA3F8 /* ReportCard.swift */,
+				90D3F157294FFFC500CEA3F8 /* UpdateGrade.swift */,
+			);
+			path = Utils;
+			sourceTree = "<group>";
+		};
 /* End PBXGroup section */
 
 /* Begin PBXNativeTarget section */
@@ -120,7 +157,14 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				90D3F15F294FFFC600CEA3F8 /* RemoveGrade.swift in Sources */,
+				90D3F160294FFFC600CEA3F8 /* ReportCard.swift in Sources */,
 				2768CA08294F453B00990B98 /* main.swift in Sources */,
+				90D3F15E294FFFC600CEA3F8 /* Exit.swift in Sources */,
+				90D3F153294FFCB300CEA3F8 /* Modules.swift in Sources */,
+				90D3F15D294FFFC600CEA3F8 /* DeleteStudent.swift in Sources */,
+				90D3F15C294FFFC600CEA3F8 /* UpdateGrade.swift in Sources */,
+				90D3F156294FFFA200CEA3F8 /* AddStudent.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/Git_ Exercise.xcodeproj/project.xcworkspace/xcuserdata/bagjaeu.xcuserdatad/UserInterfaceState.xcuserstate b/Git_ Exercise.xcodeproj/project.xcworkspace/xcuserdata/bagjaeu.xcuserdatad/UserInterfaceState.xcuserstate
new file mode 100644
index 0000000..a6edea9
Binary files /dev/null and b/Git_ Exercise.xcodeproj/project.xcworkspace/xcuserdata/bagjaeu.xcuserdatad/UserInterfaceState.xcuserstate differ
diff --git a/Git_ Exercise.xcodeproj/xcuserdata/bagjaeu.xcuserdatad/xcschemes/xcschememanagement.plist b/Git_ Exercise.xcodeproj/xcuserdata/bagjaeu.xcuserdatad/xcschemes/xcschememanagement.plist
new file mode 100644
index 0000000..9cab2b7
--- /dev/null
+++ b/Git_ Exercise.xcodeproj/xcuserdata/bagjaeu.xcuserdatad/xcschemes/xcschememanagement.plist	
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>SchemeUserState</key>
+	<dict>
+		<key>Git_ Exercise.xcscheme_^#shared#^_</key>
+		<dict>
+			<key>orderHint</key>
+			<integer>0</integer>
+		</dict>
+	</dict>
+</dict>
+</plist>
diff --git a/Git_ Exercise/Modules/Modules.swift b/Git_ Exercise/Modules/Modules.swift
new file mode 100644
index 0000000..9966f62
--- /dev/null
+++ b/Git_ Exercise/Modules/Modules.swift	
@@ -0,0 +1,91 @@
+//
+//  Modules.swift
+//  Git_ Exercise
+//
+//  Created by 박재우 on 2022/12/19.
+//
+
+import Foundation
+
+typealias Student = String
+
+class Management {
+    var students: [Student: [ReportCard]] = [:]
+}
+
+struct ReportCard {
+    var subject: String
+    var grade: String
+}
+
+enum Pattern: String {
+    case input = "^[0-9a-zA-Z+]*$"
+}
+
+enum Score: Double {
+    case APlus = 4.5
+    case AZero = 4.0
+    case BPlus = 3.5
+    case BZero = 3.0
+    case CPlus = 2.5
+    case CZero = 2.0
+    case DPlus = 1.5
+    case DZero = 1.0
+    case F = 0.0
+}
+
+enum Grade: String {
+    case APlus = "A+"
+    case AZero = "A0"
+    case BPlus = "B+"
+    case BZero = "B0"
+    case CPlus = "C+"
+    case CZero = "C0"
+    case DPlus = "D+"
+    case DZero = "D0"
+    case F = "F"
+}
+
+enum Commands: String {
+    case addStudent = "1"
+    case deleteStudent = "2"
+    case updateGrade = "3"
+    case removeGrade = "4"
+    case reportCard = "5"
+    case exit = "X"
+}
+
+enum Errors: String {
+    case main = "뭔가 입력이 잘못되었습니다. 1~5 사이의 숫자 혹은 X를 입력해주세요."
+    case input = "입력이 잘못되었습니다. 다시 확인해주세요."
+    case containStudent = "은 이미 존재하는 학생입니다. 추가하지 않습니다."
+    case searchStudent = " 학생을 찾지 못했습니다."
+    case searchSubject = " 과목을 찾지 못했습니다."
+}
+
+enum Questions: String {
+    case main = "원하는 기능을 입력해주세요\n1: 학생추가, 2: 학생삭제, 3: 성적추가(변경), 4: 성적삭제, 5: 평점보기, X: 종료"
+    case addStudent = "추가할 학생의 이름을 입력해주세요."
+    case deleteStudent = "삭제할 학생의 이름을 입력해주세요"
+    case updateGrade = "성적을 추가할 학생의 이름, 과목 이름, 성적(A+, A0, F 등)을 띄어쓰기로 구분하여 차례로 작성해주세요."
+    case removeGrade = "성적을 삭제할 학생의 이름, 과목 이름을 띄어쓰기로 구분하여 차례로 작성해주세요."
+    case reportCard = "평점을 알고 싶은 학생의 이름을 입력해주세요"
+}
+
+class Operations {
+    func addStudent(_ student: Student) {
+        print("\(student) 학생을 추가했습니다.")
+    }
+    func deleteStudent(_ student: Student) {
+        print("\(student) 학생을 삭제하였습니다.")
+    }
+    func updateGrade(_ reportCard: ReportCard, of student: Student) {
+        print("\(student) 학생의 \(reportCard.subject) 과목이 \(reportCard.grade)로 추가(변경)되었습니다.")
+    }
+    func removeGrade(_ subject: String, of student: Student) {
+        print("\(student) 학생의 \(subject) 과목의 성적이 삭제되었습니다.")
+    }
+    var exit: String {
+        return "프로그램을 종료합니다..."
+    }
+}
diff --git a/Git_ Exercise/Utils/AddStudent.swift b/Git_ Exercise/Utils/AddStudent.swift
new file mode 100644
index 0000000..343f0a6
--- /dev/null
+++ b/Git_ Exercise/Utils/AddStudent.swift	
@@ -0,0 +1,25 @@
+//
+//  AddStudent.swift
+//  Git_ Exercise
+//
+//  Created by 박재우 on 2022/12/19.
+//
+
+import Foundation
+
+func addStudent() {
+    print(Questions.addStudent.rawValue)
+    guard let student = readLine() else { return }
+    guard let _ = student.range(of: Pattern.input.rawValue, options: .regularExpression),
+          student.isEmpty == false else {
+        print(Errors.input.rawValue)
+        return
+    }
+    let isContain = manager.contains { $0.key == student }
+    guard isContain == false else {
+        print("\(student)\(Errors.containStudent.rawValue)")
+        return
+    }
+    manager[student] = []
+    Operations().addStudent(student)
+}
diff --git a/Git_ Exercise/Utils/DeleteStudent.swift b/Git_ Exercise/Utils/DeleteStudent.swift
new file mode 100644
index 0000000..1a2b46f
--- /dev/null
+++ b/Git_ Exercise/Utils/DeleteStudent.swift	
@@ -0,0 +1,25 @@
+//
+//  DeleteStudent.swift
+//  GradeManagement
+//
+//  Created by 박재우 on 2022/12/19.
+//
+
+import Foundation
+
+func deleteStudent() {
+    print(Questions.deleteStudent.rawValue)
+    guard let student = readLine() else { return }
+    guard let _ = student.range(of: Pattern.input.rawValue, options: .regularExpression),
+          student.isEmpty == false else {
+        print(Errors.input.rawValue)
+        return
+    }
+    let isContain = manager.contains { $0.key == student }
+    guard isContain else {
+        print("\(student)\(Errors.searchStudent.rawValue)")
+        return
+    }
+    manager.removeValue(forKey: student)
+    Operations().deleteStudent(student)
+}
diff --git a/Git_ Exercise/Utils/Exit.swift b/Git_ Exercise/Utils/Exit.swift
new file mode 100644
index 0000000..38a5f0c
--- /dev/null
+++ b/Git_ Exercise/Utils/Exit.swift	
@@ -0,0 +1,12 @@
+//
+//  Exit.swift
+//  GradeManagement
+//
+//  Created by 박재우 on 2022/12/19.
+//
+
+import Foundation
+
+func exit() {
+    print(Operations().exit)
+}
diff --git a/Git_ Exercise/Utils/RemoveGrade.swift b/Git_ Exercise/Utils/RemoveGrade.swift
new file mode 100644
index 0000000..40e1536
--- /dev/null
+++ b/Git_ Exercise/Utils/RemoveGrade.swift	
@@ -0,0 +1,41 @@
+//
+//  RemoveGrade.swift
+//  GradeManagement
+//
+//  Created by 박재우 on 2022/12/19.
+//
+
+import Foundation
+
+func removeGrade() {
+    print(Questions.removeGrade.rawValue)
+    guard let answer = readLine() else { return }
+    var inputs = answer.components(separatedBy: " ")
+    guard 2 == inputs.count else {
+        print(Errors.input.rawValue)
+        return
+    }
+    for input in inputs {
+        guard let _ = input.range(of: Pattern.input.rawValue, options: .regularExpression),
+              input.isEmpty == false else {
+            print(Errors.input.rawValue)
+            return
+        }
+    }
+    let student = inputs.removeFirst()
+    let isStudent = manager.contains { $0.key == student }
+    guard isStudent else {
+        print("\(student)\(Errors.searchStudent.rawValue)")
+        return
+    }
+    let subject = inputs.removeFirst()
+    guard let reports = manager[student] else {return}
+    for index in 0..<reports.count {
+        if reports[index].subject == subject {
+            manager[student]?.remove(at: index)
+            Operations().removeGrade(subject, of: student)
+            return
+        }
+    }
+    print("\(subject) \(Errors.searchSubject.rawValue)")
+}
diff --git a/Git_ Exercise/Utils/ReportCard.swift b/Git_ Exercise/Utils/ReportCard.swift
new file mode 100644
index 0000000..47eebea
--- /dev/null
+++ b/Git_ Exercise/Utils/ReportCard.swift	
@@ -0,0 +1,50 @@
+//
+//  ReportCard.swift
+//  GradeManagement
+//
+//  Created by 박재우 on 2022/12/19.
+//
+
+import Foundation
+
+func reportCard() {
+    print(Questions.reportCard.rawValue)
+    guard let student = readLine() else { return }
+    guard let _ = student.range(of: Pattern.input.rawValue, options: .regularExpression),
+          student.isEmpty == false else {
+        print(Errors.input.rawValue)
+        return
+    }
+    let isContain = manager.contains { $0.key == student }
+    guard isContain else {
+        print("\(student)\(Errors.searchStudent.rawValue)")
+        return
+    }
+    guard let reports = manager[student] else {return}
+    var average = 0.0
+    for report in reports {
+        print("\(report.subject): \(report.grade)")
+        switch Grade(rawValue: report.grade) {
+        case .APlus:
+            average += Score.APlus.rawValue
+        case .AZero:
+            average += Score.AZero.rawValue
+        case .BPlus:
+            average += Score.BPlus.rawValue
+        case .BZero:
+            average += Score.BZero.rawValue
+        case .CPlus:
+            average += Score.CPlus.rawValue
+        case .CZero:
+            average += Score.CZero.rawValue
+        case .DPlus:
+            average += Score.DPlus.rawValue
+        case .DZero:
+            average += Score.DZero.rawValue
+        default:
+            average += 0.0
+        }
+    }
+    average /= Double(reports.count)
+    print("평점 : \(average)")
+}
diff --git a/Git_ Exercise/Utils/UpdateGrade.swift b/Git_ Exercise/Utils/UpdateGrade.swift
new file mode 100644
index 0000000..90d10ea
--- /dev/null
+++ b/Git_ Exercise/Utils/UpdateGrade.swift	
@@ -0,0 +1,69 @@
+//
+//  UpdateGrade.swift
+//  GradeManagement
+//
+//  Created by 박재우 on 2022/12/19.
+//
+
+import Foundation
+
+func updateGrade() {
+    print(Questions.updateGrade.rawValue)
+    guard let answer = readLine() else { return }
+    var inputs = answer.components(separatedBy: " ")
+    guard 3 == inputs.count else {
+        print(Errors.input.rawValue)
+        return
+    }
+    for input in inputs {
+        guard let _ = input.range(of: Pattern.input.rawValue, options: .regularExpression),
+              input.isEmpty == false else {
+            print(Errors.input.rawValue)
+            return
+        }
+    }
+    
+    let student = inputs.removeFirst()
+    let isStudent = manager.contains { $0.key == student }
+    guard isStudent else {
+        print("\(student)\(Errors.searchStudent.rawValue)")
+        return
+    }
+    
+    let grade = inputs.removeLast()
+    var score = ""
+    switch Grade(rawValue: grade) {
+    case .APlus:
+        score = grade
+    case .AZero:
+        score = grade
+    case .BPlus:
+        score = grade
+    case .BZero:
+        score = grade
+    case .CPlus:
+        score = grade
+    case .CZero:
+        score = grade
+    case .DPlus:
+        score = grade
+    case .DZero:
+        score = grade
+    case .F:
+        score = grade
+    default:
+        print(Errors.input.rawValue)
+        return
+    }
+    
+    let subject = inputs.removeFirst()
+    guard let reports = manager[student] else {return}
+    for index in 0..<reports.count {
+        if reports[index].subject == subject {
+            manager[student]?.remove(at: index)
+        }
+    }
+    let report = ReportCard(subject: subject, grade: score)
+    manager[student]?.append(report)
+    Operations().updateGrade(report, of: student)
+}
diff --git a/Git_ Exercise/main.swift b/Git_ Exercise/main.swift
index 986559b..3742214 100644
--- a/Git_ Exercise/main.swift	
+++ b/Git_ Exercise/main.swift	
@@ -2,10 +2,30 @@
 //  main.swift
 //  Git_ Exercise
 //
-//  Created by 잼킹 on 2022/12/18.
+//  Created by 박재우 on 2022/12/18.
 //
 
 import Foundation
 
-print("Hello, World!")
-
+var manager = Management().students
+main: while true {
+    print(Questions.main.rawValue)
+    guard let input = readLine() else { break main }
+    switch Commands(rawValue: input) {
+    case .addStudent:
+        addStudent()
+    case .deleteStudent:
+        deleteStudent()
+    case .updateGrade:
+        updateGrade()
+    case .removeGrade:
+        removeGrade()
+    case .reportCard:
+        reportCard()
+    case .exit:
+        exit()
+        break main
+    default:
+        print(Errors.main.rawValue)
+    }
+}