diff --git a/src/main/java/com/booleanuk/core/Exercise.java b/src/main/java/com/booleanuk/core/Exercise.java
index 70ac307..ba7f657 100644
--- a/src/main/java/com/booleanuk/core/Exercise.java
+++ b/src/main/java/com/booleanuk/core/Exercise.java
@@ -40,60 +40,74 @@ public String sayGoodMorning(boolean isMorning) {
     // 1. What will the returned value be if I run sayGoodMorning(false)?
     // Change the returned value in the method below to your answer. It is case-sensitive.
     public String one() {
-        return "";
+        return "Good day!";
     }
 
     // 2. What will the output be if I run sayGoodMorning(true)?
     // Change the returned value in the method below to your answer. It is case-sensitive.
     public String two() {
-        return "";
+        return "Good morning!";
     }
 
     // 3. What will the output be if I run sayGoodMorning("Hello".equals("Hello"))?
     // Change the returned value in the method below to your answer. It is case-sensitive.
     public String three() {
-        return "";
+        return "Good morning!";
     }
 
     // 4. What will the output be if I run sayGoodMorning(!"A word".equals("Another word"))
     public String four() {
-        return "";
+        return "Good morning!";
     }
 
     // 5. What will the output be if I run sayGoodMorning(25 != 25)
     public String five() {
-        return "";
+        return "Good day!";
     }
 
     // 6. Use a conditional statement to return "Correct!" if the input is more than 7
     // or "Wrong!" if not
     public String six(int num) {
-        return "Not implemented yet!";
+        if (num > 7) {
+            return "Correct!";
+        }
+        else {
+            return "Wrong!";
+        }
     }
 
     // 7. Use a conditional statement to return "Correct!" if the input is false
     // or "Wrong!" if not
     public String seven(boolean bool) {
-        return "Not implemented yet!";
+        if (!bool) {
+            return "Correct!";
+        } else {
+            return "Wrong!";
+        }
     }
 
     // 8. Use a conditional statement to return "Correct!" if numOne is more than or equal to numTwo
     // or "Wrong!" if not
     public String eight(int numOne, int numTwo) {
-        return "Not implemented yet!";
+        if (numOne >= numTwo) {
+            return "Correct!";
+        }
+        else {
+            return "Wrong!";
+        }
     }
 
     // 9. Use a conditional statement to return true if the array provided is not empty
     // or false if it is empty
     public boolean nine(int[] nums) {
-        return false;
+        return (!(nums == null) && !(nums.length == 0));
     }
 
     // 10. Use a conditional statement to return true if the provided string contains the word
     // "milk", or false if not
     // https://www.w3schools.com/java/java_ref_string.asp
     public boolean ten(String sentence) {
-        return false;
+        return sentence.contains("milk");
     }
 
     // 11. Use conditional statements to return the number 3 if the provided string contains
@@ -101,13 +115,17 @@ public boolean ten(String sentence) {
     // Return the number 9 if the string contains both coffee and milk.
     // Otherwise, return the number 0.
     public int eleven(String sentence) {
-        return -1;
+        if (sentence.contains("milk") && sentence.contains("coffee")) return 9;
+        else if (sentence.contains("milk")) return 3;
+        else if (sentence.contains("coffee")) return 6;
+        else return 0;
     }
 
     // 12. Use conditional statements to return true if num is more than or equal to lower and is
     // less than or equal to upper, otherwise return false.
     public boolean twelve(int num, int lower, int upper) {
-        return false;
+        if (num >= lower && num <= upper) return true;
+        else return false;
     }
 
     /*
@@ -123,6 +141,11 @@ public boolean twelve(int num, int lower, int upper) {
         20+     | Adult
      */
     public String thirteen(int age) {
-        return "Not implemented yet!";
+        if (age == 0) return "Baby";
+        else if (1 <= age && age <= 4) return "Toddler";
+        else if (5 <= age && age <= 12) return "Child";
+        else if (13 <= age && age <= 19) return "Teenager";
+        else if (20 <= age) return "Adult";
+        return null;
     }
 }
diff --git a/src/main/java/com/booleanuk/extension/Extension.java b/src/main/java/com/booleanuk/extension/Extension.java
index 44e540f..25f12f7 100644
--- a/src/main/java/com/booleanuk/extension/Extension.java
+++ b/src/main/java/com/booleanuk/extension/Extension.java
@@ -13,7 +13,11 @@ public class Extension extends ExtensionBase {
         "The cake is still baking!" if there are any remaining minutes left,
         and "The timer finished ages ago!" if the remaining minutes is a negative number
      */
-
+    public String timerStatus(int minutesLeft) {
+        if (minutesLeft == 0) return "The cake is ready!";
+        else if (minutesLeft > 0) return "The cake is still baking!";
+        else return "The timer finished ages ago!";
+    }
 
 
 
@@ -26,7 +30,11 @@ public class Extension extends ExtensionBase {
         provided and the prep time per ingredient.
         If a prep time of 0 is provided, the method should assume each ingredient takes 2 minutes to prepare.
      */
+    public int estimatePrepTime(String[] ingredients, int prepTime) {
+        if (prepTime == 0) prepTime = 2;
 
+        return ingredients.length * prepTime;
+    }
 
 
     /*  3.
@@ -40,7 +48,14 @@ public class Extension extends ExtensionBase {
 
         You may need to use programming techniques we have yet to cover in the course to solve this task.
      */
-
+    public int calculateGramsOfSugar(String[] ingredients, int numLayers) {
+        boolean needsSugar = false;
+        for (int i = 0; i < ingredients.length; i ++) {
+            if (ingredients[i].toLowerCase().equals("sugar")) needsSugar = true;
+        }
+        if (needsSugar) return 100 * numLayers;
+        return 0;
+    }