diff --git a/session-01/validators.js b/session-01/validators.js
index 56ea66d..cae4ea7 100644
--- a/session-01/validators.js
+++ b/session-01/validators.js
@@ -7,7 +7,22 @@
   - username cannot contain special characters
 */
 function validUsername(username) {
-  return;
+  // Check length
+  if (username.length < 3 || username.length > 10) {
+    return false;
+  }
+
+  // Check if it begins with a letter
+  if (!/^[a-zA-Z]/.test(username)) {
+    return false;
+  }
+
+  // Check if it only contains letters and numbers
+  if (!/^[a-zA-Z0-9]+$/.test(username)) {
+    return false;
+  }
+
+  return true;
 }
 
 /*
@@ -17,7 +32,21 @@ function validUsername(username) {
   - password must contain at least 1 letter, 1 number, and 1 special character
 */
 function validPassword(password) {
-  return;
+  // Check length
+  if (password.length < 10 || password.length > 64) {
+    return false;
+  }
+
+  // Check for at least 1 letter, 1 number, and 1 special character
+  const hasLetter = /[a-zA-Z]/.test(password);
+  const hasNumber = /[0-9]/.test(password);
+  const hasSpecialChar = /[!@#$%^&*(),.?":{}|<>]/.test(password);
+
+  if (!hasLetter || !hasNumber || !hasSpecialChar) {
+    return false;
+  }
+
+  return true;
 }
 
 module.exports = { validUsername, validPassword };
diff --git a/session-02/exercise.js b/session-02/exercise.js
index 6ade818..61d0e3b 100644
--- a/session-02/exercise.js
+++ b/session-02/exercise.js
@@ -1,22 +1,25 @@
-/*
-  Transform the input array of strings into uppercase strings
-  For example, for the input ["cat", "hat"], return ["CAT", "HAT"]
-*/
+/**
+ * Transform the input array of strings into uppercase strings.
+ * @param {string[]} listOfStrings - An array of strings to transform.
+ * @returns {string[]} An array of strings in uppercase.
+ */
 function transformArrayToUpper(listOfStrings) {
-  return;
+  return listOfStrings.map(string => string.toUpperCase());
 }
 
-/*
-  Write a function that returns the sum of all student ages.
-  The function will be passed an array of objects and the result
-  will be the sum of all ages.
-  - Note, not all objects will contain an age. Omit these objects.
-  For example, for the input:
-    [{ name: 'Sandra', age: 31 }, {}, { name: 'Didi', age: 20}]
-    the function should return 51
-*/
+/**
+ * Write a function that returns the sum of all student ages.
+ * The function will be passed an array of objects, and the result
+ * will be the sum of all ages.
+ * Note, not all objects will contain an age. Omit these objects.
+ * @param {Object[]} listOfStudentObjects - Array of student objects.
+ * @returns {number} The sum of ages of students with an 'age' property.
+ */
 function sumOfAllAges(listOfStudentObjects) {
-  return;
+  return listOfStudentObjects
+    .filter(student => student.age !== undefined) // Filter objects that have an age property
+    .reduce((sum, student) => sum + student.age, 0); // Sum up the ages
 }
 
 module.exports = { transformArrayToUpper, sumOfAllAges };
+
diff --git a/session-03/js-patterns.js b/session-03/js-patterns.js
index 5291252..21bdbe3 100644
--- a/session-03/js-patterns.js
+++ b/session-03/js-patterns.js
@@ -23,6 +23,9 @@ let driverAge = 16; // try changing to 16 or greater
 driverAge >= 16 && console.log("this person can drive");
 
 // Ternary operator: ( ? : )
+let luckyNumber = 8; // Define luckyNumber
+let guess = 8; // Define guess
+
 let result = luckyNumber === guess ? "right" : "wrong";
 
 // let result = "";