diff --git a/1-exercises/A-undefined/exercise.js b/1-exercises/A-undefined/exercise.js
index 0acfc78d..7630f112 100644
--- a/1-exercises/A-undefined/exercise.js
+++ b/1-exercises/A-undefined/exercise.js
@@ -13,15 +13,20 @@
 let a;
 console.log(a);
 
+//a is not defined
+
 
 // Example 2
 function sayHello() {
     let message = "Hello";
 }
+// the message is not defined
 
 let hello = sayHello();
 console.log(hello);
 
+// hello is not defined
+
 
 // Example 3
 function sayHelloToUser(user) {
@@ -30,7 +35,11 @@ function sayHelloToUser(user) {
 
 sayHelloToUser();
 
+//user is not defined
+
 
 // Example 4
 let arr = [1,2,3];
 console.log(arr[3]);
+
+// array no 3 does not exist
diff --git a/1-exercises/B-while-loop/exercise.js b/1-exercises/B-while-loop/exercise.js
index b459888f..9af69c91 100644
--- a/1-exercises/B-while-loop/exercise.js
+++ b/1-exercises/B-while-loop/exercise.js
@@ -7,6 +7,16 @@
 
 function evenNumbers(n) {
     // TODO
+    let array = [];
+    let i = 0;
+    while (n > array.length) {
+      if (i % 2 === 0) {
+        array.push(i);
+      }
+      i++;
+    }
+
+    console.log(array);
 }
 
 evenNumbers(3); // should output 0,2,4
diff --git a/1-exercises/C-while-loop-with-array/exercise.js b/1-exercises/C-while-loop-with-array/exercise.js
index d584cd75..9eebc1de 100644
--- a/1-exercises/C-while-loop-with-array/exercise.js
+++ b/1-exercises/C-while-loop-with-array/exercise.js
@@ -18,6 +18,11 @@ const BIRTHDAYS = [
 
 function findFirstJulyBDay(birthdays) {
     // TODO
+	let i = 0;
+  while (i < birthdays.length) {
+    if (birthdays[i].includes("July")) return birthdays[i];
+    i++;
+  }
 }
 
 console.log(findFirstJulyBDay(BIRTHDAYS)); // should output "July 11th"
diff --git a/1-exercises/D-do-while/exercise.js b/1-exercises/D-do-while/exercise.js
index f10d0764..ae24fd3c 100644
--- a/1-exercises/D-do-while/exercise.js
+++ b/1-exercises/D-do-while/exercise.js
@@ -8,8 +8,6 @@
 
 function evenNumbersSum(n) {
     // TODO
-}
-
 console.log(evenNumbersSum(3)); // should output 6
 console.log(evenNumbersSum(0)); // should output 0
 console.log(evenNumbersSum(10)); // should output 90
\ No newline at end of file