diff --git a/index.js b/index.js
index f61169392..23c8bfd2f 100644
--- a/index.js
+++ b/index.js
@@ -48,8 +48,8 @@ function processFirstItem(stringList, callback) {
  * [2] Invoking `processLength` passing `[]` and `(num) => "There are " + num`,
  * should return "There are 0".
 */
-function processLength(/* CODE HERE */) {
-  /* CODE HERE */
+function processLength(list, callback) {
+  return callback(list.length);
 }
 
 /**
@@ -66,8 +66,8 @@ function processLength(/* CODE HERE */) {
  * Invoking `processLastItem` passing `['foo', 'bar']` and `(str) => str + str`,
  * should return 'barbar'.
 */
-function processLastItem(/* CODE HERE */) {
-  /* CODE HERE */
+function processLastItem(stringList, callback) {
+  return callback(stringList[stringList.length -1]);
 }
 
 /**
@@ -88,8 +88,8 @@ function processLastItem(/* CODE HERE */) {
  * [2] Invoking `processSum` passing `-5`, '-1', and `(num) => num + 1000`,
  * should return 994.
 */
-function processSum(/* CODE HERE */) {
-  /* CODE HERE */
+function processSum(num1,  num2, callback) {
+  return callback(num1 + num2);
 }
 
 /**
@@ -110,8 +110,8 @@ function processSum(/* CODE HERE */) {
  * [2] Invoking `processProduct` passing 25 and 0 and `(num) => num + 1000`,
  * should return 1000.
 */
-function processProduct(/* CODE HERE */) {
-  /* CODE HERE */
+function processProduct(num1, num2, callback) {
+  return callback (num1 * num2);
 }
 
 /**
@@ -155,8 +155,12 @@ function processDuplicateFree(/* CODE HERE ONLY AFTER COMPLETING ALL OTHER TASKS
  * 
  * [2] Invoking `lowerCaseStrings` with `['a', 'b', 'c' ]` will return `[ 'a', 'b', 'c' ]`.
 */
-function lowerCaseStrings(/* code here */) {
-  /* code here */
+function lowerCaseStrings(strings) {
+ let lowerCase = [];
+ strings.forEach((string)=> {
+   lowerCase.push(string.toLowerCase());
+ })
+ return lowerCase;
 }
 
 /**
@@ -174,8 +178,14 @@ function lowerCaseStrings(/* code here */) {
  * 
  * [2] Invoking `isItAnApple` with `['a', 'b', 'c' ]` will return `[ false, false, false ]`.
 */
-function isItAnApple(/* code here */) {
-  /* code here */
+function isItAnApple(strings) {
+   const newString = strings.map((boolean) => {
+   if (boolean === 'apple')
+   return true;
+   else (boolean !== 'apple')
+   return false;
+  });
+  return newString;
 }
 
 /**
@@ -194,8 +204,8 @@ function isItAnApple(/* code here */) {
  * 
  * [2] Invoking `removeApple` with `['a', 'b', 'c' ]` will return `[ 'a', 'b', 'c' ]`.
 */
-function removeApple(/* code here */) {
-  /* code here */
+function removeApple(strings) {
+  return strings.filter(fruit => fruit !== 'apple');
 }
 
 /**
@@ -213,8 +223,8 @@ function removeApple(/* code here */) {
  * 
  * [2] Invoking `stringSmash` with `['a', 'b', 'c' ]` will return `abc`.
 */
-function stringSmash(/* code here */) {
-  /* code here */
+function stringSmash(strings) {
+  return strings.reduce((total, item) => { return total += item });
 }
 
 // A local community center is holding a fund raising 5k fun run and has invited
@@ -232,8 +242,16 @@ function stringSmash(/* code here */) {
  * @returns an array with all the runners' full names in the following format: "Smith, John".
  * The full names appear in the array in the same order the runners appear in the `runners` array.
 */
-function getFullNames(/* CODE HERE */) {
-  /* CODE HERE */
+function getFullNames(runners) {
+  const fullNames = [];
+
+  runners.forEach((runner) => { return fullNames.push(`${runner.last_name}, ${runner.first_name}`); });
+
+  return fullNames;
+  // const fullName = runners.map((name) => {
+  //   return `${runners.last_name}, ${runners.first_name}`;
+  // });
+  // return fullName;
 }
 
 /**
@@ -248,8 +266,9 @@ function getFullNames(/* CODE HERE */) {
  * @returns an array with all the runners' first names in ALL CAPS.
  * The first names appear in the array in the same order the runners appear in the `runners` array.
 */
-function firstNamesAllCaps(/* CODE HERE */) {
-  /* CODE HERE */
+function firstNamesAllCaps(runners) {
+  return runners.map((item) => { return item.first_name.toUpperCase()
+  });
 }
 
 /**
@@ -295,11 +314,16 @@ function tallyUpDonations(/* CODE HERE */) {
  * Study the code for counter1 and counter2. Answer the questions below.
  * 
  * 1. What is the difference between counter1 and counter2?
+ *    counter1 has a variable and a function nested inside of it. This function is different 
+ * from counter 2 function because the nested function within can store and recall information
+ * that was processed.
  * 
  * 2. Which of the two uses a closure? How can you tell?
+ *    counter1 has a closure. I can tell because it has a nested function which accessed a variable 
+ * outside of it.
  * 
  * 3. In what scenario would the counter1 code be preferable? In what scenario would counter2 be better? 
- *
+ *   counter1 would be preferable if you ......////////
 */
 
 // counter1 code