diff --git a/session-01/validators.js b/session-01/validators.js
index 56ea66d..3ec47c4 100644
--- a/session-01/validators.js
+++ b/session-01/validators.js
@@ -7,7 +7,18 @@
   - username cannot contain special characters
 */
 function validUsername(username) {
-  return;
+  if (username.length < 3 || username.length > 10){
+    return false;
+  }
+  else if (username[0].match(/[a-z]/i) === null){
+    return false;
+  }
+  else if (username.match(/[^a-zA-Z0-9]/) !== null){
+    return false;
+  }
+  else {
+    return true;
+  }
 }
 
 /*
@@ -17,7 +28,21 @@ function validUsername(username) {
   - password must contain at least 1 letter, 1 number, and 1 special character
 */
 function validPassword(password) {
-  return;
+  if (password.length < 10 || password.length > 64){
+    return false;
+  }
+  else if (password.match(/[a-zA-Z]/) === null){
+    return false;
+  }
+  else if (password.match(/[0-9]/) === null){
+    return false;
+  }
+  else if (password.match(/[^a-zA-Z0-9]/) === null){
+    return false;
+  }
+  else {
+    return true;
+  }
 }
 
 module.exports = { validUsername, validPassword };
diff --git a/session-02/exercise.js b/session-02/exercise.js
index 6ade818..0823e44 100644
--- a/session-02/exercise.js
+++ b/session-02/exercise.js
@@ -3,7 +3,10 @@
   For example, for the input ["cat", "hat"], return ["CAT", "HAT"]
 */
 function transformArrayToUpper(listOfStrings) {
-  return;
+  for (let i = 0; i < listOfStrings.length; i++) {
+    listOfStrings[i] = listOfStrings[i].toUpperCase();
+  }
+  return listOfStrings;
 }
 
 /*
@@ -16,7 +19,13 @@ function transformArrayToUpper(listOfStrings) {
     the function should return 51
 */
 function sumOfAllAges(listOfStudentObjects) {
-  return;
+  let sum = 0;
+  for (let i = 0; i < listOfStudentObjects.length; i++) {
+    if (listOfStudentObjects[i].age) {
+      sum += listOfStudentObjects[i].age;
+    }
+  }
+  return sum;
 }
 
 module.exports = { transformArrayToUpper, sumOfAllAges };