Completed

MathUtilities.java

      * @return sum of `baseValue` and `difference`
      */
     public Integer add(int baseValue, int difference) {
-        return null;
+        int sum = baseValue + difference;
+        return sum;
     }
 
     /**
      * @return sum of `baseValue` and `difference`
      */
     public Long add(long baseValue, long difference) {
-        return null;
+        long sum = baseValue + difference;
+        return sum;
     }
 
     /**
      * @return sum of `baseValue` and `difference`
      */
     public Short add(short baseValue, short difference) {
-        return null;
+        short sum = (short)(baseValue + difference);
+        return sum;
     }
 
     /**
      * @return sum of `baseValue` and `difference`
      */
     public Byte add(byte baseValue, byte difference) {
-        return null;
+        byte sum = (byte)(baseValue + difference);
+        return sum;
     }
 
     /**
      * @return sum of `baseValue` and `difference`
      */
     public Float add(float baseValue, float difference) {
-        return null;
+        float sum = baseValue + difference;
+        return sum;
     }
 
     /**
      * @return sum of `baseValue` and `difference`
      */
     public Double add(double baseValue, double difference) {
-        return null;
+        double sum = baseValue + difference;
+        return sum;
     }
 
     /**
      * @return difference between `baseValue` and `difference`
      */
     public Integer subtract(int baseValue, int difference) {
-        return null;
+        int result = baseValue - difference;
+        return result;
     }
 
     /**
      * @return difference between `baseValue` and `difference`
      */
     public Long subtract(long baseValue, long difference) {
-        return null;
+        long result = baseValue - difference;
+        return result;
     }
 
     /**
      * @return difference between `baseValue` and `difference`
      */
     public Short subtract(short baseValue, short difference) {
-        return null;
+        short result = (short)(baseValue - difference);
+        return result;
     }
 
     /**
      * @return difference between `baseValue` and `difference`
      */
     public Byte subtract(byte baseValue, byte difference) {
-        return null;
+        byte result = (byte)(baseValue - difference);
+        return result;
     }
 
     /**
      * @return difference between `baseValue` and `difference`
      */
     public Float subtract(float baseValue, float difference) {
-        return null;
+        float result = baseValue - difference;
+        return result;
     }
 
     /**
      * @return difference between `baseValue` and `difference`
      */
     public Double subtract(double baseValue, double difference) {
-        return null;
+        double result = baseValue - difference;
+        return result;
     }
 
 
      * @return division of `dividend` by `divisor
      */
     public Integer divide(int dividend, int divisor) {
-        return null;
+        int quotient = dividend/divisor;
+        return quotient;
     }
 
     /**
      * @return division of `dividend` by `divisor
      */
     public Long divide(long dividend, long divisor) {
-        return null;
+        long quotient = dividend/divisor;
+        return quotient;
     }
 
     /**
      * @return division of `dividend` by `divisor
      */
     public Short divide(short dividend, short divisor) {
-        return null;
+        short quotient = (short)(dividend/divisor);
+        return quotient;
     }
 
     /**
      * @return division of `dividend` by `divisor
      */
     public Byte divide(byte dividend, byte divisor) {
-        return null;
+        byte quotient = (byte)(dividend/divisor);
+        return quotient;
     }
 
     /**
      * @return division of `dividend` by `divisor
      */
     public Float divide(float dividend, float divisor) {
-        return null;
+        float quotient = dividend/divisor;
+        return quotient;
     }
 
     /**
      * @return division of `dividend` by `divisor
      */
     public Double divide(double dividend, double divisor) {
-        return null;
+        double quotient = dividend/divisor;
+        return quotient;
     }
 
 
      * @return product of `multiplicand` by `multiplier`
      */
     public Integer multiply(int multiplicand, int multiplier) {
-        return null;
+        int product = multiplicand * multiplier;
+        return product;
     }
 
     /**
      * @return product of `multiplicand` by `multiplier`
      */
     public Long multiply(long multiplicand, long multiplier) {
-        return null;
+        long product = multiplicand * multiplier;
+        return product;
     }
 
     /**
      * @return product of `multiplicand` by `multiplier`
      */
     public Short multiply(short multiplicand, short multiplier) {
-        return null;
+        short product = (short)(multiplicand * multiplier);
+        return product;
     }
     /**
      * @param multiplicand value to be multiplied
      * @return product of `multiplicand` by `multiplier`
      */
     public Byte multiply(byte multiplicand, byte multiplier) {
-        return null;
+        byte product = (byte)(multiplicand * multiplier);
+        return product;
     }
 
     /**
      * @return product of `multiplicand` by `multiplier`
      */
     public Float multiply(float multiplicand, float multiplier) {
-        return null;
+        float product = multiplicand * multiplier;
+        return product;
     }
 
     /**
      * @return product of `multiplicand` by `multiplier`
      */
     public Double multiply(double multiplicand, double multiplier) {
-        return null;
+        double product = multiplicand * multiplier;
+        return product;
     }
 
 
       * @return true
      */
     public Boolean returnTrue() {
-        return null;
+        boolean a = true;
+        return a;
     }
 
     /**
      * @return false
      */
     public Boolean returnFalse() {
-        return null;
+        boolean b = false;
+        return b;
     }
 
 }

PredicateUtilities.java

      * @return true if `x` is greater than `y`
      */
     public Boolean isGreaterThan(int x, int y) {
-        return null;
+        return (x>y);
     }
 
     /**
      * @return true if `x` is less than `y`
      */
     public Boolean isLessThan(int x, int y) {
-        return null;
+        return (x<y);
     }
 
     /**
      * @return true if `x` is greater than or equal to `y`
      */
     public Boolean isGreaterThanOrEqualTo(int x, int y) {
-        return null;
+        return (x>=y);
     }
 
     /**
      * @return true if `x` is less than or equal to `y`
      */
     public Boolean isLessThanOrEqualTo(int x, int y) {
-        return null;
+        return (x<=y);
     }
 }

StringUtilities.java

      * @return `Hello World` as a string
      */
     public static String getHelloWorld() {
-        return null;
+        return ("Hello World");
     }
 
     /**
      * @return the concatenation of two strings, `firstSegment`, and `secondSegment`
      */
     public static String concatenation(String firstSegment, String secondSegment){
-        return null;
+        return firstSegment + secondSegment;
     }
 
     /**
      * @return the concatenation of an integer, `firstSegment`, and a String, `secondSegment`
      */
     public static String concatenation(int firstSegment, String secondSegment){
-        return null;
+        return firstSegment + secondSegment;
     }
 
     /**
      * @return the first 3 characters of `input`
      */
     public static String getPrefix(String input){
-        return null;
+        return input.substring(0,3);
     }
 
     /**
      * @return the last 3 characters of `input`
      */
     public static String getSuffix(String input){
-        return null;
+        return input.substring(input.length() - 3);
     }
 
     /**
      * @return the equivalence of two strings, `inputValue` and `comparableValue`
      */
     public static Boolean compareTwoStrings(String inputValue, String comparableValue){
-        return null;
+        return (inputValue.equals(comparableValue));
     }
 
     /**
      * @return the middle character of `inputValue`
      */
     public static Character getMiddleCharacter(String inputValue){
-        return null;
+        int middleChar = inputValue.length()/2;
+        if (middleChar%2 == 0) 
+        {
+        return inputValue.charAt(middleChar-1);
+        }
+        else
+        return inputValue.charAt(middleChar);
     }
 
     /**
      * @return the first sequence of characters
      */
     public static String getFirstWord(String spaceDelimitedString){
-        return null;
+        String strSplit[] = spaceDelimitedString.split(" ",2);
+        String firstWord = strSplit[0];
+        return firstWord;
     }
 
     /**
      * @return the second word of a string delimited by spaces.
      */
     public static String getSecondWord(String spaceDelimitedString){
-        return null;
+        String strSplit[] = spaceDelimitedString.split(" ",0);
+        String secondWord = strSplit[1];
+        return secondWord;
     }
 
     /**
      * @return an identical string with characters in reverse order.
      */
     public static String reverse(String stringToReverse){
-        return null;
+        String strReversed = new StringBuilder(stringToReverse).reverse().toString();
+        return strReversed;
     }
 }