diff --git a/100DaysOfSwift/Day5/Accepting parameters.swift b/100DaysOfSwift/Day5/Accepting parameters.swift
new file mode 100644
index 0000000..57b8662
--- /dev/null
+++ b/100DaysOfSwift/Day5/Accepting parameters.swift	
@@ -0,0 +1,10 @@
+// Accepting parameters
+// https://www.hackingwithswift.com/sixty/5/2/accepting-parameters
+
+print("Hello, world!")
+
+func square(number: Int) {
+    print(number * number)
+}
+
+square(number: 8)
\ No newline at end of file
diff --git a/100DaysOfSwift/Day5/Default parameters.swift b/100DaysOfSwift/Day5/Default parameters.swift
new file mode 100644
index 0000000..27e6131
--- /dev/null
+++ b/100DaysOfSwift/Day5/Default parameters.swift	
@@ -0,0 +1,13 @@
+// Default parameters
+// https://www.hackingwithswift.com/sixty/5/6/default-parameters
+
+func greet(_ person: String, nicely: Bool = true) {
+    if nicely == true {
+        print("Hello, \(person)!")
+    } else {
+        print("Oh no, it's \(person) again...")
+    }
+}
+
+greet("Taylor")
+greet("Taylor", nicely: false)
\ No newline at end of file
diff --git a/100DaysOfSwift/Day5/Omitting parameter labels.swift b/100DaysOfSwift/Day5/Omitting parameter labels.swift
new file mode 100644
index 0000000..b83a870
--- /dev/null
+++ b/100DaysOfSwift/Day5/Omitting parameter labels.swift	
@@ -0,0 +1,8 @@
+// Omitting parameter labels
+// https://www.hackingwithswift.com/sixty/5/5/omitting-parameter-labels
+
+func greet(_ person: String) {
+    print("Hello, \(person)!")
+}
+
+greet("Taylor")
\ No newline at end of file
diff --git a/100DaysOfSwift/Day5/Parameter labels.swift b/100DaysOfSwift/Day5/Parameter labels.swift
new file mode 100644
index 0000000..a988404
--- /dev/null
+++ b/100DaysOfSwift/Day5/Parameter labels.swift	
@@ -0,0 +1,14 @@
+// Parameter labels
+// https://www.hackingwithswift.com/sixty/5/4/parameter-labels
+
+func square(number: Int) -> Int {
+    return number * number
+}
+let result = square(number: 8)
+
+// -------------------------------------------------------------
+
+func sayHello(to name: String) {
+    print("Hello, \(name)!")
+}
+sayHello(to: "Taylor")
\ No newline at end of file
diff --git a/100DaysOfSwift/Day5/README.md b/100DaysOfSwift/Day5/README.md
new file mode 100644
index 0000000..7aac759
--- /dev/null
+++ b/100DaysOfSwift/Day5/README.md
@@ -0,0 +1,16 @@
+# Day #5
+
+---
+
+**What I learned about**
+
+- **[Writing functions](/100DaysOfSwift/Day5/Writing%20functions.swift)**
+- **[Accepting parameters](/100DaysOfSwift/Day5/Accepting%20parameters.swift)**
+- **[Returning values](/100DaysOfSwift/Day5/Returning%20values.swift)**
+- **[Parameter labels](/100DaysOfSwift/Day5/Parameter%20labelss.swift)**
+- **[Omitting parameter labels](/100DaysOfSwift/Day5/Omitting%20parameter%20labels.swift)**
+- **[Default parameters](/100DaysOfSwift/Day5/Default%20parameters.swift)**
+- **[Variadic functions](/100DaysOfSwift/Day5/Variadic%20functions.swift)**
+- **[Writing throwing functions](/100DaysOfSwift/Day5/Writing%20throwing%20functions.swift)**
+- **[Running throwing functions](/100DaysOfSwift/Day5/Running%20throwing%20functions.swift)**
+- **[inout parameters](/100DaysOfSwift/Day5/inout%20parameters.swift)**
\ No newline at end of file
diff --git a/100DaysOfSwift/Day5/Returning values.swift b/100DaysOfSwift/Day5/Returning values.swift
new file mode 100644
index 0000000..cc428a0
--- /dev/null
+++ b/100DaysOfSwift/Day5/Returning values.swift	
@@ -0,0 +1,9 @@
+// Returning values
+// https://www.hackingwithswift.com/sixty/5/3/returning-values
+
+func square(number: Int) -> Int {
+    return number * number
+}
+
+let result = square(number: 8)
+print(result)
\ No newline at end of file
diff --git a/100DaysOfSwift/Day5/Running throwing functions.swift b/100DaysOfSwift/Day5/Running throwing functions.swift
new file mode 100644
index 0000000..a9d576c
--- /dev/null
+++ b/100DaysOfSwift/Day5/Running throwing functions.swift	
@@ -0,0 +1,11 @@
+// Running throwing functions
+// https://www.hackingwithswift.com/sixty/5/9/running-throwing-functions
+
+do {
+    try checkPassword("password")
+    print("That password is good!")
+} catch {
+    print("You can't use that password.")
+}
+
+// do starts a section of code that might cause problems, try is used before every function that might throw an error, and catch lets you handle errors gracefully.
\ No newline at end of file
diff --git a/100DaysOfSwift/Day5/Variadic functions.swift b/100DaysOfSwift/Day5/Variadic functions.swift
new file mode 100644
index 0000000..25b53c1
--- /dev/null
+++ b/100DaysOfSwift/Day5/Variadic functions.swift	
@@ -0,0 +1,11 @@
+// Variadic functions
+// https://www.hackingwithswift.com/sixty/5/7/variadic-functions
+
+print("Haters", "gonna", "hate")
+
+func square(numbers: Int...) {
+    for number in numbers {
+        print("\(number) squared is \(number * number)")
+    }
+}
+square(numbers: 1, 2, 3, 4, 5)
\ No newline at end of file
diff --git a/100DaysOfSwift/Day5/Writing functions.swift b/100DaysOfSwift/Day5/Writing functions.swift
new file mode 100644
index 0000000..e5527f7
--- /dev/null
+++ b/100DaysOfSwift/Day5/Writing functions.swift	
@@ -0,0 +1,15 @@
+// Writing function
+// https://www.hackingwithswift.com/sixty/5/1/writing-functions
+
+func printHelp() {
+    let message = """
+Welcome to MyApp!
+
+Run this app inside a directory of images and
+MyApp will resize them all into thumbnails
+"""
+
+    print(message)
+}
+
+printHelp()
\ No newline at end of file
diff --git a/100DaysOfSwift/Day5/Writing throwing functions.swift b/100DaysOfSwift/Day5/Writing throwing functions.swift
new file mode 100644
index 0000000..567be22
--- /dev/null
+++ b/100DaysOfSwift/Day5/Writing throwing functions.swift	
@@ -0,0 +1,14 @@
+// Writing throwing functions
+// https://www.hackingwithswift.com/sixty/5/8/writing-throwing-functions
+
+enum PasswordError: Error {
+    case obvious
+}
+
+func checkPassword(_ password: String) throws -> Bool {
+    if password == "password" {
+        throw PasswordError.obvious
+    }
+
+    return true
+}
\ No newline at end of file
diff --git a/100DaysOfSwift/Day5/inout parameters.swift b/100DaysOfSwift/Day5/inout parameters.swift
new file mode 100644
index 0000000..0af17a2
--- /dev/null
+++ b/100DaysOfSwift/Day5/inout parameters.swift	
@@ -0,0 +1,2 @@
+// inout parameters
+// https://www.hackingwithswift.com/sixty/5/10/inout-parameters
\ No newline at end of file
diff --git a/100DaysOfSwift/README.md b/100DaysOfSwift/README.md
index 57444e4..4a9c8df 100644
--- a/100DaysOfSwift/README.md
+++ b/100DaysOfSwift/README.md
@@ -13,4 +13,5 @@
 - **[Day #1](/100DaysOfSwift/Day1/)** - variables, simple data types, and string interpolation
 - **[Day #2](/100DaysOfSwift/Day2/)** - arrays, dictionaries, sets, and enums
 - **[Day #3](/100DaysOfSwift/Day3/)** - operators and conditions
-- **[Day #4](/100DaysOfSwift/Day4/)** - loops, loops, and more loops
\ No newline at end of file
+- **[Day #4](/100DaysOfSwift/Day4/)** - loops, loops, and more loops
+- **[Day #5](/100DaysOfSwift/Day5/)** - functions, parameters, and errors
\ No newline at end of file
diff --git a/100DaysOfSwiftUI/README.md b/100DaysOfSwiftUI/README.md
index 0f33aed..5eb9448 100644
--- a/100DaysOfSwiftUI/README.md
+++ b/100DaysOfSwiftUI/README.md
@@ -1,7 +1,17 @@
-# [100 Days of SwiftUI](https://www.hackingwithswift.com/100/swiftui)
+# [100 Days of Swift](https://www.hackingwithswift.com/100/swiftui)
 
 ---
 
 **This folder is for the [100 Days of SwiftUI](https://www.hackingwithswift.com/100/swiftui) challenge.**
 
 **NOTE:** This is **[100 Days of SwiftUI](https://www.hackingwithswift.com/100/swiftui)**, not **[100 Days of Swift](https://www.hackingwithswift.com/100)** which is located [here](/100DaysOfSwift/)
+
+---
+
+**Days 1-12: Introduction to Swift**
+
+- **[Day #1](/100DaysOfSwift/Day1/)** - variables, simple data types, and string interpolation
+- **[Day #2](/100DaysOfSwift/Day2/)** - arrays, dictionaries, sets, and enums
+- **[Day #3](/100DaysOfSwift/Day3/)** - operators and conditions
+- **[Day #4](/100DaysOfSwift/Day4/)** - loops, loops, and more loops
+- **[Day #5](/100DaysOfSwift/Day5/)** - functions, parameters, and errors
\ No newline at end of file