diff --git a/src/main/java/LoopFun.java b/src/main/java/LoopFun.java
index 801ab56..e0d4bbd 100644
--- a/src/main/java/LoopFun.java
+++ b/src/main/java/LoopFun.java
@@ -1,4 +1,4 @@
- 
+import java.util.Locale;
 
 public class LoopFun
 {
@@ -10,8 +10,12 @@ public class LoopFun
        * @return the factorial of the number
        */
       public Integer factorial(Integer number){
-          return null;
-      }
+          int result = 1;
+          for (int i = number; i > 0; i--) {
+              result *= i;
+          }
+          return result;
+      } //passed
 
       /**
        * Given a phrase, get the acronym of that phrase. Acronym is the combination of
@@ -21,8 +25,13 @@ public Integer factorial(Integer number){
        * @return Upper case string of the first letter of each word
        */
       public String acronym(String phrase) {
-          return null;
-      }
+          String result = "";
+          for (String s : phrase.split("\\s")) {
+              result += s.charAt(0);
+          }
+          result = result.toUpperCase();
+          return result;
+      } //passed
 
       /**
        * To prevent anyone from reading our messages, we can encrypt it so it will only be readable by its
@@ -37,6 +46,20 @@ public String acronym(String phrase) {
        * @return the encrypted string by shifting each character by three character
        */
       public String encrypt(String word) {
-          return null;
-      }
+          char[] ch = word.toCharArray();
+          for (int i = 0; i < ch.length; i++) {
+              if (ch[i] == 'x') {
+                  ch[i] -= 26;
+              }
+              if (ch[i] == 'y') {
+                  ch[i] -= 26;
+              }
+              if (ch[i] == 'z') {
+                  ch[i] -= 26;
+              }
+              ch[i] += 3;
+          }
+          String result = new String(ch);
+          return result;
+      } //passed
 }
diff --git a/src/main/java/MathUtilities.java b/src/main/java/MathUtilities.java
index e067c75..b0359d0 100644
--- a/src/main/java/MathUtilities.java
+++ b/src/main/java/MathUtilities.java
@@ -9,8 +9,9 @@ public class MathUtilities{
    * @return the sum of the two numbers
    */
   public Integer add(Integer baseValue, Integer valueToAdd){
-      return null;
-  }
+      Integer result = baseValue + valueToAdd;
+      return result;
+  } //passed
 
   /**
    * Add two number together
@@ -19,8 +20,9 @@ public Integer add(Integer baseValue, Integer valueToAdd){
    * @return the sum of the two numbers
    */
   public Double add(Double baseValue, Double valueToAdd){
-      return null;
-  }
+      Double result = baseValue + valueToAdd;
+      return result;
+  } //passed
 
   /**
    * Get half the value of the number
@@ -28,8 +30,9 @@ public Double add(Double baseValue, Double valueToAdd){
    * @return the half of the number in double
    */
   public Double half(Integer number) {
-      return null;
-  }
+      Double result = (number.doubleValue() / 2);
+      return result;
+  } //passed
 
   /**
    * Determine if the number is odd
@@ -37,8 +40,11 @@ public Double half(Integer number) {
    * @return true if the number is odd, false if it is even
    */
   public Boolean isOdd(Integer number){
-      return null;
-  }
+      if (number % 2 != 0) {
+          return true;
+      }
+      return false;
+  } //passed
 
 
   /**
@@ -47,7 +53,7 @@ public Boolean isOdd(Integer number){
    * @return the result of the number multiply by itself
    */
   public Integer square(Integer number) {
-      return null;
-  }
+      return number * number;
+  } //passed
 
 }
diff --git a/src/main/java/StringUtilities.java b/src/main/java/StringUtilities.java
index e3ea8a9..ea7bd16 100644
--- a/src/main/java/StringUtilities.java
+++ b/src/main/java/StringUtilities.java
@@ -1,12 +1,11 @@
-
 public class StringUtilities {
     /**
      * @param input value to be returned
      * @return `input`
      */
     public String returnInput(String input) {
-        return null;
-    }
+        return input;
+    } //passed
 
     /**
      * @param baseValue value to be added to
@@ -14,24 +13,32 @@ public String returnInput(String input) {
      * @return the concatenation of `baseValue` and `valueToBeAdded`
      */
     public String concatenate(String baseValue, String valueToBeAdded) {
-        return null;
-    }
+        String result = baseValue.concat(valueToBeAdded);
+        return result;
+    } //passed
 
     /**
      * @param valueToBeReversed value to be reversed
      * @return identical string with characters in opposite order
      */
     public String reverse(String valueToBeReversed) {
-        return null;
-    }
+        StringBuilder sb = new StringBuilder();
+        for(int i=valueToBeReversed.length()-1;i>=0;i--) {
+            sb.append(valueToBeReversed.charAt(i));
+        }
+        String result = sb.toString();
+        return result;
+    } //passed
 
     /**
      * @param word word to get middle character of
      * @return middle character of `word`
      */
     public Character getMiddleCharacter(String word) {
-        return null;
-    }
+        int length = word.length();
+        int middle = length / 2;
+        return word.charAt(middle);
+    } //passed
 
     /**
      * @param value value to have character removed from
@@ -39,14 +46,17 @@ public Character getMiddleCharacter(String word) {
      * @return `value` with char of value `charToRemove` removed
      */
     public String removeCharacter(String value, Character charToRemove) {
-        return null;
-    }
+        String str = value.replace(charToRemove.toString(),"");
+        return str;
+    } //passed
 
     /**
      * @param sentence String delimited by spaces representative of a sentence
      * @return last `word` in sentence
      */
     public String getLastWord(String sentence) {
-        return null;
-    }
+        String[] strArr = sentence.split("\\s");
+        String result = strArr[strArr.length-1];
+        return result;
+    } //passed
 }