diff --git a/index.js b/index.js
index f61169392..e72b25eb1 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.pop())
 }
 
 /**
@@ -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)
 }
 
 /**
@@ -132,8 +132,8 @@ function processProduct(/* CODE HERE */) {
  * [2] Invoking `processDuplicateFree` passing `[1,1,2,2,3]` and `(arr) => arr.length`,
  * should return 3.
 */
-function processDuplicateFree(/* CODE HERE ONLY AFTER COMPLETING ALL OTHER TASKS */) {
-  /* CODE HERE ONLY AFTER COMPLETING ALL OTHER TASKS */
+function processDuplicateFree(list) {
+  
 }
 
 /////////////// HIGHER-ORDER ARRAY METHODS ///////////////
@@ -155,8 +155,13 @@ 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) {
+  const lower = [];
+    strings.forEach((item) => {
+    lower.push(item.toLowerCase())
+   
+});
+return lower
 }
 
 /**
@@ -174,8 +179,13 @@ 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) {
+  return (strings.map((item) => {
+   if(item === 'apple'){
+    return true;} else {
+   return false;
+   }
+ }));
 }
 
 /**
@@ -194,8 +204,10 @@ function isItAnApple(/* code here */) {
  * 
  * [2] Invoking `removeApple` with `['a', 'b', 'c' ]` will return `[ 'a', 'b', 'c' ]`.
 */
-function removeApple(/* code here */) {
-  /* code here */
+function removeApple(string) {
+ return string.filter((fruits) => {
+return (fruits !== 'apple')
+ });
 }
 
 /**
@@ -213,8 +225,10 @@ 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((accm, touch) => {
+  return accm + touch;
+});
 }
 
 // A local community center is holding a fund raising 5k fun run and has invited
@@ -232,8 +246,11 @@ 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 full = runners.map((item) =>{
+   return `${item.last_name}, ${item.first_name}`
+ });
+ return full;
 }
 
 /**
@@ -248,8 +265,11 @@ 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) {
+  const caps = runners.map((item) =>{
+   return item.first_name.toUpperCase();
+ });
+  return caps;
 }
 
 /**
@@ -266,8 +286,13 @@ function firstNamesAllCaps(/* CODE HERE */) {
  * @returns an array containing only the runners that use the given `tShirtSize`.
  * The runners in the array appear in the same order they appear in the `runners` array.
 */
-function getRunnersByTShirtSize(/* CODE HERE */) {
-  /* CODE HERE */
+function getRunnersByTShirtSize(runners , tShirtSize) {
+  return runners.filter((item) =>{
+    return (runners + tShirtSize)
+ 
+  });
+
+ 
 }
 
 /**