diff --git a/src/main/java/LoopFun.java b/src/main/java/LoopFun.java
index 801ab56..f259c51 100644
--- a/src/main/java/LoopFun.java
+++ b/src/main/java/LoopFun.java
@@ -10,7 +10,12 @@ public class LoopFun
        * @return the factorial of the number
        */
       public Integer factorial(Integer number){
-          return null;
+          if(number == 0) {
+              return 1;
+          }
+          int addToNum = factorial(number -1);
+          int result = number * addToNum;
+          return result;
       }
 
       /**
@@ -21,7 +26,11 @@ public Integer factorial(Integer number){
        * @return Upper case string of the first letter of each word
        */
       public String acronym(String phrase) {
-          return null;
+          StringBuilder result = new StringBuilder();
+          for(String s : phrase.split(" ")){
+              result.append(s.charAt(0));
+          }
+          return (result.toString().toUpperCase());
       }
 
       /**
@@ -37,6 +46,8 @@ public String acronym(String phrase) {
        * @return the encrypted string by shifting each character by three character
        */
       public String encrypt(String word) {
+//        StringBuilder working = new StringBuilder();
+//        for(
           return null;
       }
 }
diff --git a/src/main/java/MathUtilities.java b/src/main/java/MathUtilities.java
index e067c75..7dd93ac 100644
--- a/src/main/java/MathUtilities.java
+++ b/src/main/java/MathUtilities.java
@@ -9,7 +9,7 @@ public class MathUtilities{
    * @return the sum of the two numbers
    */
   public Integer add(Integer baseValue, Integer valueToAdd){
-      return null;
+      return baseValue + valueToAdd;
   }
 
   /**
@@ -19,7 +19,7 @@ public Integer add(Integer baseValue, Integer valueToAdd){
    * @return the sum of the two numbers
    */
   public Double add(Double baseValue, Double valueToAdd){
-      return null;
+      return baseValue + valueToAdd;
   }
 
   /**
@@ -28,7 +28,7 @@ public Double add(Double baseValue, Double valueToAdd){
    * @return the half of the number in double
    */
   public Double half(Integer number) {
-      return null;
+      return Double.valueOf((number / 2));
   }
 
   /**
@@ -37,7 +37,9 @@ 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;
   }
 
 
@@ -47,7 +49,7 @@ public Boolean isOdd(Integer number){
    * @return the result of the number multiply by itself
    */
   public Integer square(Integer number) {
-      return null;
+      return (number * number);
   }
 
 }
diff --git a/src/main/java/StringUtilities.java b/src/main/java/StringUtilities.java
index e3ea8a9..039002e 100644
--- a/src/main/java/StringUtilities.java
+++ b/src/main/java/StringUtilities.java
@@ -5,7 +5,7 @@ public class StringUtilities {
      * @return `input`
      */
     public String returnInput(String input) {
-        return null;
+        return input;
     }
 
     /**
@@ -14,7 +14,7 @@ public String returnInput(String input) {
      * @return the concatenation of `baseValue` and `valueToBeAdded`
      */
     public String concatenate(String baseValue, String valueToBeAdded) {
-        return null;
+        return baseValue + valueToBeAdded;
     }
 
     /**
@@ -22,7 +22,10 @@ public String concatenate(String baseValue, String valueToBeAdded) {
      * @return identical string with characters in opposite order
      */
     public String reverse(String valueToBeReversed) {
-        return null;
+        StringBuilder makeReverseString = new StringBuilder(valueToBeReversed);
+        StringBuilder reversedStr = makeReverseString.reverse();
+        return reversedStr.toString();
+
     }
 
     /**
@@ -39,14 +42,18 @@ public Character getMiddleCharacter(String word) {
      * @return `value` with char of value `charToRemove` removed
      */
     public String removeCharacter(String value, Character charToRemove) {
-        return null;
+       StringBuilder newString = new StringBuilder(value.replaceAll("charToRemove", ""));
+       return newString.toString();
     }
 
+
     /**
      * @param sentence String delimited by spaces representative of a sentence
      * @return last `word` in sentence
      */
     public String getLastWord(String sentence) {
-        return null;
-    }
+        String result = sentence.substring(sentence.lastIndexOf(" ")+1);
+
+        return result;
+   }
 }