diff --git a/algorithm_FreeCodeCamp/argument_Unite_Unique.js b/algorithm_FreeCodeCamp/argument_Unite_Unique.js
new file mode 100644
index 0000000..c3bab69
--- /dev/null
+++ b/algorithm_FreeCodeCamp/argument_Unite_Unique.js
@@ -0,0 +1,25 @@
+function uniteUnique(arr) {
+  // Creates an empty array to store our final result.
+  var finalArray = [];
+
+  // Loop through the arguments object to truly made the program work with two or more arrays
+  // instead of 3.
+  for (var i = 0; i < arguments.length; i++) {
+    var arrayArguments = arguments[i];
+
+    // Loops through the array at hand
+    for (var j = 0; j < arrayArguments.length; j++) {
+      var indexValue = arrayArguments[j];
+
+      // Checks if the value is already on the final array.
+      if (finalArray.indexOf(indexValue) < 0) {
+        finalArray.push(indexValue);
+      }
+    }
+  }
+
+  console.log(finalArray)
+  ;
+}
+
+uniteUnique([1, 2, 3], [5, 2, 1, 4], [2, 1], [6, 7, 8]);
diff --git a/algorithm_FreeCodeCamp/binary_Agent.js b/algorithm_FreeCodeCamp/binary_Agent.js
new file mode 100644
index 0000000..17bef88
--- /dev/null
+++ b/algorithm_FreeCodeCamp/binary_Agent.js
@@ -0,0 +1,23 @@
+function binaryAgent(str) {
+  var wordArr = str.split(" ");
+  var newWordArr = [];
+  for (var i = 0; i < wordArr.length; i++){
+    newWord = String.fromCharCode(readCode(wordArr[i]));
+    newWordArr.push(newWord);
+  }
+  
+  return newWordArr.join("");
+}
+
+function readCode(string){
+  var newString = string.split("");
+  var sum = 0;
+  var count = newString.length-1; 
+  var a = [];
+  for(var i=0; i<newString.length; i++){
+    sum += (newString[i]*(Math.pow(2,count)));
+    count-=1;
+  }
+  return sum;
+}
+binaryAgent(("01000001 01110010 01100101 01101110 00100111 01110100 00100000 01100010 01101111 01101110 01100110 01101001 01110010 01100101 01110011 00100000 01100110 01110101 01101110 00100001 00111111"));
\ No newline at end of file
diff --git a/algorithm_FreeCodeCamp/cash_Register.js b/algorithm_FreeCodeCamp/cash_Register.js
new file mode 100644
index 0000000..ad05144
--- /dev/null
+++ b/algorithm_FreeCodeCamp/cash_Register.js
@@ -0,0 +1,69 @@
+var changes = {
+    "ONE HUNDRED": 100.00,
+    TWENTY:20.00,
+    TEN:10.00,
+    FIVE:5.00,
+    ONE:1.00,
+    QUARTER:0.25,
+    DIME:0.10,
+    NICKEL:0.05,
+    PENNY:0.01
+  };
+
+function checkCashRegister(price, cash, cid) {
+  var change = fpFix(cash - price);
+  var totalChange = readTotal(cid);
+  if(change == totalChange){
+    return "Closed";
+  } else if(change > totalChange){
+    return "Insufficient Funds";
+  } else{
+    return changeCash(change,cid);
+  } 
+}
+
+function readTotal(arr){
+  var total = 0; 
+  for(var j = 0; j < arr.length; j++ ){
+     total = fpFix(total + arr[j][1]); 
+  }
+  return total;
+}
+
+function changeCash(total,arr){
+   var change = ["ONE HUNDRED","TWENTY","TEN","FIVE","ONE","QUARTER","DIME","NICKEL","PENNY"];
+   var result = [];
+   var num =0;
+   var cashNum = 0;
+   var c;
+   var output;   
+   for(var i=0; i < arr.length; i++){
+     c = changes[change[i]];
+     if( c <= total){
+         num = Math.floor(total/c);  //2
+         cashNum = arr[arr.length -1 - i][1]; //60 
+       if( fpFix(num*c) > cashNum  ){
+           total = fpFix(total - cashNum);
+           output = parseFloat(Math.round(cashNum * 100) / 100).toFixed(2);
+           result.push([change[i],Number(output)]);      
+       } else{
+         total = fpFix(total - num*c);
+         output = parseFloat(Math.round(num*c * 100) / 100).toFixed(2);
+         result.push([change[i],Number(output)]); 
+       }     
+      }//if 
+     } //for
+  
+  if(total == 0){
+      return result;
+  } else{
+    return "Insufficient Funds";
+  }  
+} // function
+
+var fpFix = function (n) {
+    return Math.round(n * 100)/100;
+};
+
+
+changeCash(42.10, [["PENNY", 1.01], ["NICKEL", 2.05], ["DIME", 3.10], ["QUARTER", 4.25], ["ONE", 90.00], ["FIVE", 55.00], ["TEN", 20.00], ["TWENTY", 60.00], ["ONE HUNDRED", 100.00]]);
\ No newline at end of file
diff --git a/algorithm_FreeCodeCamp/check_For_Palindromes.js b/algorithm_FreeCodeCamp/check_For_Palindromes.js
new file mode 100644
index 0000000..25c94cd
--- /dev/null
+++ b/algorithm_FreeCodeCamp/check_For_Palindromes.js
@@ -0,0 +1,25 @@
+function palindrome(str) {
+  // Good luck!
+  // var newStr = str.replace(/[^a-zA-Z0-9]+/g, "").toLowerCase();
+  // var checkNum = newStr.length/2;
+  // var checkStr ="";
+  // var oriStr ="";
+
+  // if(newStr.length%2==0){
+  //   checkStr = newStr.slice(checkNum).split("").reverse().join("");
+  //   oriStr = newStr.slice(0,checkNum).split("").join("");
+  //   return (checkStr === oriStr);
+  // } else{
+  //   checkStr = newStr.slice(checkNum+0.5).split("").reverse().join("");
+  //   oriStr = newStr.slice(0,checkNum-0.5).split("").join("");
+  //   return (checkStr === oriStr);
+  // }
+
+  var newStr = str.replace(/[^a-zA-Z0-9]+/g, "").toLowerCase();
+  var revStr = newStr.split("").reverse().join("");
+  return (revStr === newStr);
+  
+}
+
+
+palindrome("never odd or even");
diff --git a/algorithm_FreeCodeCamp/chunky_Monkey.js b/algorithm_FreeCodeCamp/chunky_Monkey.js
new file mode 100644
index 0000000..f29a71d
--- /dev/null
+++ b/algorithm_FreeCodeCamp/chunky_Monkey.js
@@ -0,0 +1,9 @@
+function chunkArrayInGroups(arr, size) {
+  var result = []; 
+  for ( var i=0; i< arr.length / size ; i++){
+     result.push(arr.slice(size*i,size*(i+1)));
+  }
+  return result;
+}  
+
+chunkArrayInGroups([0, 1, 2, 3, 4], 3);
diff --git a/algorithm_FreeCodeCamp/confirm_the_Ending.js b/algorithm_FreeCodeCamp/confirm_the_Ending.js
new file mode 100644
index 0000000..c690be8
--- /dev/null
+++ b/algorithm_FreeCodeCamp/confirm_the_Ending.js
@@ -0,0 +1,6 @@
+function confirmEnding(str, target) {
+  var subStr = str.substr(-target.length);
+  return (subStr === target);
+}
+
+confirmEnding("Bastian", "n");
\ No newline at end of file
diff --git a/algorithm_FreeCodeCamp/convertHTML.js b/algorithm_FreeCodeCamp/convertHTML.js
new file mode 100644
index 0000000..7d888b9
--- /dev/null
+++ b/algorithm_FreeCodeCamp/convertHTML.js
@@ -0,0 +1,18 @@
+function convertHTML(str) {
+  // &colon;&rpar;
+  map = {'&':'&amp;',
+          '<':'&lt;',
+          '>':'&gt;',
+          '\"':'&quot;',
+          '\'':"&apos;"
+        };
+  
+  mapArr = Object.keys(map);
+  for(var n in mapArr){
+    word = mapArr[n];
+    str = str.replace(RegExp(word, 'g'),map[word]);
+  }
+  return str;
+}
+
+convertHTML("Hamburgers < Pizza < Tacos");
diff --git a/algorithm_FreeCodeCamp/diff_two_Arrays.js b/algorithm_FreeCodeCamp/diff_two_Arrays.js
new file mode 100644
index 0000000..717a5b9
--- /dev/null
+++ b/algorithm_FreeCodeCamp/diff_two_Arrays.js
@@ -0,0 +1,18 @@
+function diffArray(arr1, arr2) {
+  var newArr = [];
+  for(var i =0; i<arr2.length; i++){
+    if(arr1.indexOf(arr2[i]) === -1){
+      newArr.push(arr2[i]);
+    }
+  }
+  
+  for(var j =0; j<arr1.length; j++){
+    if(arr2.indexOf(arr1[j]) === -1){
+      newArr.push(arr1[j]);
+    }
+  }
+  
+   return newArr;
+}
+
+diffArray(["diorite", "andesite", "grass", "dirt", "pink wool", "dead shrub"], ["diorite", "andesite", "grass", "dirt", "dead shrub"]);
\ No newline at end of file
diff --git a/algorithm_FreeCodeCamp/drop_Element.js b/algorithm_FreeCodeCamp/drop_Element.js
new file mode 100644
index 0000000..2c5cfc0
--- /dev/null
+++ b/algorithm_FreeCodeCamp/drop_Element.js
@@ -0,0 +1,13 @@
+function dropElements(arr, func) {
+  var len = arr.length;
+  for(var num = 0; num < len; num++){
+    if(func(arr[0])){
+      break;
+    }else{
+      arr.shift();
+    }
+  }
+  return arr;
+}
+
+dropElements([1, 2, 3, 4], function(n) {return n > 5;});
diff --git a/algorithm_FreeCodeCamp/factorialize_Number.js b/algorithm_FreeCodeCamp/factorialize_Number.js
new file mode 100644
index 0000000..7934616
--- /dev/null
+++ b/algorithm_FreeCodeCamp/factorialize_Number.js
@@ -0,0 +1,9 @@
+function factorialize(num) {
+  var result = 1;
+  for(var i=1;i<=num;i++){
+    result *= i;
+  }
+  return result;
+}
+
+factorialize(5);
\ No newline at end of file
diff --git a/algorithm_FreeCodeCamp/falsy_Bouncer.js b/algorithm_FreeCodeCamp/falsy_Bouncer.js
new file mode 100644
index 0000000..fc7c592
--- /dev/null
+++ b/algorithm_FreeCodeCamp/falsy_Bouncer.js
@@ -0,0 +1,7 @@
+function bouncer(arr) {
+  return arr.filter(function(num){
+    return Boolean(num) == true;
+  });
+}
+
+bouncer([7, "ate", "", false, 9]);
diff --git a/algorithm_FreeCodeCamp/findLongest_in_String.js b/algorithm_FreeCodeCamp/findLongest_in_String.js
new file mode 100644
index 0000000..67bc8b5
--- /dev/null
+++ b/algorithm_FreeCodeCamp/findLongest_in_String.js
@@ -0,0 +1,13 @@
+function findLongestWord(str) {
+  
+  arrStr = str.split(" ");
+  for (var i=0;i<arrStr.length-1;i++){
+    if(arrStr[i].length > arrStr[i+1].length){
+      arrStr[i+1] = arrStr[i];
+    }
+  }
+    return arrStr[arrStr.length-1].length;
+    }
+
+findLongestWord("The quick brown fox jumped over the lazy dog");
+
diff --git a/algorithm_FreeCodeCamp/finder_Keepers.js b/algorithm_FreeCodeCamp/finder_Keepers.js
new file mode 100644
index 0000000..bea0a8c
--- /dev/null
+++ b/algorithm_FreeCodeCamp/finder_Keepers.js
@@ -0,0 +1,7 @@
+function findElement(arr, func) {
+   filterArr = arr.filter(func);
+    
+  return filterArr[0];
+}
+
+findElement([1, 2, 3, 4], function(num){ return num % 2 === 0; });
diff --git a/algorithm_FreeCodeCamp/get_Index_to_Ins.js b/algorithm_FreeCodeCamp/get_Index_to_Ins.js
new file mode 100644
index 0000000..a539a85
--- /dev/null
+++ b/algorithm_FreeCodeCamp/get_Index_to_Ins.js
@@ -0,0 +1,15 @@
+function getIndexToIns(arr, num) {
+  // Find my place in this sorted array.
+  sortArr = arr.sort(function(a,b){
+    return a-b;
+  });
+  
+  for(var i=0; i<arr.length; i++){
+    if(sortArr[i]>=num){
+      return i;
+    }
+   }
+   return arr.length;
+}
+
+getIndexToIns([2, 5, 10], 15);
diff --git a/algorithm_FreeCodeCamp/inventery_Update.js b/algorithm_FreeCodeCamp/inventery_Update.js
new file mode 100644
index 0000000..e14c148
--- /dev/null
+++ b/algorithm_FreeCodeCamp/inventery_Update.js
@@ -0,0 +1,50 @@
+
+function updateInventory(arr1, arr2) {
+    for (var i = 0; i < arr2.length; i++) {
+      var foundMatch = false;
+      // use each arr2's property to test if it's also on arr1
+      for (var j = 0; j < arr1.length; j ++) {
+        // if yes, add the value
+      if (arr1[j][1].indexOf(arr2[i][1]) !== -1) {
+        arr1[j][0] += arr2[i][0];
+           foundMatch = true;
+        } 
+      }
+      // end of testing, the one didn't be found need to be push into arr1
+      if(foundMatch == false){
+            arr1.push(arr2[i]);
+        }
+      
+  }
+  return sortArr(arr1);
+}
+
+// Example inventory lists
+var curInv = [
+    [21, "Bowling Ball"],
+    [2, "Dirty Sock"],
+    [1, "Hair Pin"],
+    [5, "Microphone"]
+];
+
+var newInv = [
+    [2, "Hair Pin"],
+    [3, "Half-Eaten Apple"],
+    [67, "Bowling Ball"],
+    [7, "Toothpaste"]
+];
+
+
+
+function sortArr(arr){
+  return arr.sort(function(a,b){
+    if(a[1]>b[1]){
+      return 1;
+    } else {
+      return -1;
+    }
+    
+  });
+}
+
+updateInventory([[21, "Bowling Ball"], [2, "Dirty Sock"], [1, "Hair Pin"], [5, "Microphone"]], [[2, "Hair Pin"], [3, "Half-Eaten Apple"], [67, "Bowling Ball"], [7, "Toothpaste"]]);
diff --git a/algorithm_FreeCodeCamp/largest_Numbers_in_Arrays.js b/algorithm_FreeCodeCamp/largest_Numbers_in_Arrays.js
new file mode 100644
index 0000000..99cee86
--- /dev/null
+++ b/algorithm_FreeCodeCamp/largest_Numbers_in_Arrays.js
@@ -0,0 +1,12 @@
+function largestOfFour(arr) {
+  result = [];
+  for(var i=0; i<arr.length ; i++){
+     arr[i].sort(function(a, b){
+        return b-a;
+    });
+     result.push(arr[i][0]);             
+   }
+  return result;
+}
+
+largestOfFour([[4, 5, 1, 3], [13, 27, 18, 26], [32, 35, 37, 39], [1000, 1001, 857, 1]]);
diff --git a/algorithm_FreeCodeCamp/map_the_Debris.js b/algorithm_FreeCodeCamp/map_the_Debris.js
new file mode 100644
index 0000000..8cc8dc7
--- /dev/null
+++ b/algorithm_FreeCodeCamp/map_the_Debris.js
@@ -0,0 +1,11 @@
+function orbitalPeriod(arr) {
+  var GM = 398600.4418;
+  var earthRadius = 6367.4447;
+  return arr.map(function(el){
+    return {name:el.name,
+            orbitalPeriod:Math.round((2*Math.PI)*Math.sqrt(Math.pow(earthRadius+el.avgAlt,3)/GM))
+    };
+  });
+}
+
+orbitalPeriod([{name : "sputnik", avgAlt : 35873.5553}]);
diff --git a/algorithm_FreeCodeCamp/merge_Bird.js b/algorithm_FreeCodeCamp/merge_Bird.js
new file mode 100644
index 0000000..f496623
--- /dev/null
+++ b/algorithm_FreeCodeCamp/merge_Bird.js
@@ -0,0 +1,19 @@
+function migratoryBirds(n, ar) {
+    var result = {};
+    for(var i = 0; i < ar.length; i++) {
+    if(!result[ar[i]]){
+       result[ar[i]] = 0;
+    }
+        result[ar[i]]++;
+    }
+    
+    var ans = result[ar[0]];
+    for(var k = 0; k< ar.length-1; k++){
+        if (result[ar[k]] < result[ar[k+1]] ){
+            ans = ar[k+1];
+        }
+    }
+    return ans;
+  }
+
+  // use !result[ar[i]] to make sure if tehre is an object existed.
\ No newline at end of file
diff --git a/algorithm_FreeCodeCamp/missing_Letter.js b/algorithm_FreeCodeCamp/missing_Letter.js
new file mode 100644
index 0000000..976d169
--- /dev/null
+++ b/algorithm_FreeCodeCamp/missing_Letter.js
@@ -0,0 +1,9 @@
+function fearNotLetter(str) {
+   for(var i=0; i<str.length-1 ; i++){
+     if (str.charCodeAt(i+1) - str.charCodeAt(i)!== 1){
+       return String.fromCharCode(str.charCodeAt(i)+1);
+     }
+   }
+}
+
+fearNotLetter("abce");
diff --git a/algorithm_FreeCodeCamp/mutations.js b/algorithm_FreeCodeCamp/mutations.js
new file mode 100644
index 0000000..e15b140
--- /dev/null
+++ b/algorithm_FreeCodeCamp/mutations.js
@@ -0,0 +1,10 @@
+function mutation(arr) {
+  var newArr = arr[1].toLowerCase().split("");
+  for (var i=0 ; i< arr[1].length; i++){
+    if (arr[0].toLowerCase().indexOf(newArr[i]) == -1){
+      return false;
+    } 
+  }
+  return true;
+}  
+mutation(["floor", "for"]);
\ No newline at end of file
diff --git a/algorithm_FreeCodeCamp/no_Repeat.js b/algorithm_FreeCodeCamp/no_Repeat.js
new file mode 100644
index 0000000..2c6c328
--- /dev/null
+++ b/algorithm_FreeCodeCamp/no_Repeat.js
@@ -0,0 +1,26 @@
+function permAlone(str) {
+  var arr = str.split('');
+  var result = 0; //counter
+  
+  function swap(a,b){
+    var temp = arr[a];
+    arr[a] = arr[b];
+    arr[b] = temp;
+  } // take two els swap position
+function generate(n){
+  var regex =/([a-z])\1+/;
+  
+  if( n === 1 && !regex.test(arr.join(""))){
+    result += 1;
+  } else{
+    for (var i =0 ; i !== n; i++){
+      generate( n -1 );
+      swap(n % 2 ? 0 : i, n -1);
+    }
+  }
+}
+  generate(arr.length);
+  return result;
+}// function
+
+permAlone('aab');
diff --git a/algorithm_FreeCodeCamp/object_Model.js b/algorithm_FreeCodeCamp/object_Model.js
new file mode 100644
index 0000000..a30ca17
--- /dev/null
+++ b/algorithm_FreeCodeCamp/object_Model.js
@@ -0,0 +1,26 @@
+
+   var Person = function(firstAndLast) {
+    // Complete the method below and implement the others similarly
+    var fullName = firstAndLast;
+    this.getFirstName = function(){
+      return fullName.split(" ")[0];
+    };
+    this.getLastName = function(){
+      return fullName.split(" ")[1];
+    };
+     this.getFullName = function(){
+       return fullName;
+     };
+     this.setFirstName = function(first){
+       fullName = first + " " + fullName.split(" ")[1];
+     };
+     this.setLastName = function(last){
+       fullName = fullName.split(" ")[0] + " " + last;
+     };
+     this.setFullName = function(full){
+       fullName = full ;
+     };
+};
+
+var bob = new Person('Bob Ross');
+bob.getFirstName();
diff --git a/algorithm_FreeCodeCamp/object_Search**.js b/algorithm_FreeCodeCamp/object_Search**.js
new file mode 100644
index 0000000..1cf40a9
--- /dev/null
+++ b/algorithm_FreeCodeCamp/object_Search**.js
@@ -0,0 +1,14 @@
+function whatIsInAName(collection, source) {
+
+  var srcKeys = Object.keys(source);
+  return collection.filter(function(obj){
+    for (var n in srcKeys){
+      if(!obj.hasOwnProperty(srcKeys[n])||obj[srcKeys[n]]!=source[srcKeys[n]]){
+          return false;
+         }
+       }
+     return true;
+  });
+}
+
+whatIsInAName([{ first: "Romeo", last: "Montague" }, { first: "Mercutio", last: null }, { first: "Tybalt", last: "Capulet" }], { last: "Capulet" });
diff --git a/algorithm_FreeCodeCamp/oddFib.Sum.js b/algorithm_FreeCodeCamp/oddFib.Sum.js
new file mode 100644
index 0000000..750cce8
--- /dev/null
+++ b/algorithm_FreeCodeCamp/oddFib.Sum.js
@@ -0,0 +1,24 @@
+
+function sumFibs(num) {
+  return sumOdd(giveFibs(num));
+}
+
+function giveFibs(num){
+  fib=[1,1];
+  for(var i=2; fib[i-2]+fib[i-1]<=num ; i++){
+   fib.push(fib[i-1]+fib[i-2]);
+ } 
+  return fib;
+}
+
+function sumOdd(arr){
+  var sum=0;
+  for(var n in arr){
+    if(arr[n]%2 !==0){
+      sum += arr[n];
+    }
+  }
+    return sum;
+}
+
+sumFibs(75025);
\ No newline at end of file
diff --git a/algorithm_FreeCodeCamp/pairDNA.js b/algorithm_FreeCodeCamp/pairDNA.js
new file mode 100644
index 0000000..b2581de
--- /dev/null
+++ b/algorithm_FreeCodeCamp/pairDNA.js
@@ -0,0 +1,43 @@
+
+// function pairElement(str) {
+//  var newStr = str.split("");
+//  var result = [];
+//  var a =["A","T"];
+//  var b =["T","A"];
+//  var c =["C","G"];
+//  var d =["G","C"];
+  
+//  for(var num in newStr){
+//    if(newStr[num] == "A"){
+//      result.push(a);
+//    } else if(newStr[num] == "T"){
+//      result.push(b);
+//    } else if(newStr[num] == "C"){
+//      result.push(c);
+//    } else{
+//      result.push(d);
+//    }
+//  }
+  
+//   return result;
+// }
+
+// //AT TA CG GC
+
+// pairElement("GCG");
+
+
+function pairElement(str) {
+  map = {T:"A",A:"T",C:"G",G:"C"};
+  newStrArr = str.split("");
+  for(var n in newStr){
+    newStrArr[n] = [newStrArr[n],map[newStrArr[n]]];
+  }
+  
+  return newStrArr;
+//AT TA CG GC
+
+}
+pairElement("GCG");
+
+
diff --git a/algorithm_FreeCodeCamp/pair_Wise.js b/algorithm_FreeCodeCamp/pair_Wise.js
new file mode 100644
index 0000000..d8b7bb5
--- /dev/null
+++ b/algorithm_FreeCodeCamp/pair_Wise.js
@@ -0,0 +1,20 @@
+
+function pairwise(arr, arg) {
+   var sum = 0;
+   for (var j=0;j<arr.length;j++) {
+     for (var i=j+1; i<arr.length;++i) {
+         if(arr[i] + arr[j] == arg) {
+           sum += i + j;
+           arr[i] = 'a';
+           arr[j] = 'b';
+         }
+       }
+     }
+  
+return sum;
+}
+
+
+pairwise([0, 0, 0, 0, 1, 1], 1);
+
+
diff --git a/algorithm_FreeCodeCamp/repeat_String.js b/algorithm_FreeCodeCamp/repeat_String.js
new file mode 100644
index 0000000..3a9761e
--- /dev/null
+++ b/algorithm_FreeCodeCamp/repeat_String.js
@@ -0,0 +1,9 @@
+function repeatStringNumTimes(str, num) {
+  result = "";
+  for(i=0 ; i<num ; i++){
+   result += str;
+  }
+  return result;
+}
+
+repeatStringNumTimes("abc", 3);
\ No newline at end of file
diff --git a/algorithm_FreeCodeCamp/reserve_String.js b/algorithm_FreeCodeCamp/reserve_String.js
new file mode 100644
index 0000000..347dd64
--- /dev/null
+++ b/algorithm_FreeCodeCamp/reserve_String.js
@@ -0,0 +1,16 @@
+// function reverseString(str) {
+//   var result = [];
+//   var rev_str = str.split("");
+//   for (var i=rev_str.length-1; i>=0; i--){
+//     result.push(rev_str[i]);
+//   }
+//   return result.join("");
+// }
+
+function reverseString(str) {
+  var result = [];
+  var rev_str = str.split("");
+  return rev_str.reverse().join("");
+}
+
+reverseString("hello");
diff --git a/algorithm_FreeCodeCamp/roman_Numeral_Converter.js b/algorithm_FreeCodeCamp/roman_Numeral_Converter.js
new file mode 100644
index 0000000..cb6a7e1
--- /dev/null
+++ b/algorithm_FreeCodeCamp/roman_Numeral_Converter.js
@@ -0,0 +1,19 @@
+function convertToRoman(num) {
+
+  var decimalValue = [ 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 ];
+  var romanNumeral = [ 'M', 'CM', 'D', 'CD', 'C', 'XC', 'L', 'XL', 'X', 'IX', 'V', 'IV', 'I' ];
+
+  var romanized = '';
+
+  for (var i = 0; i < decimalValue.length; i++) {
+    while (decimalValue[i] <= num) {
+      romanized += romanNumeral[i];
+      num -= decimalValue[i];
+    }
+  }
+
+  return romanized;
+}
+  
+  
+convertToRoman(36);
\ No newline at end of file
diff --git a/algorithm_FreeCodeCamp/search_n_Replace.js b/algorithm_FreeCodeCamp/search_n_Replace.js
new file mode 100644
index 0000000..664cd77
--- /dev/null
+++ b/algorithm_FreeCodeCamp/search_n_Replace.js
@@ -0,0 +1,11 @@
+function myReplace(str, before, after) {
+  
+  if(before.charAt(0) == before.charAt(0).toUpperCase()){
+      return str.replace(before,after.charAt(0).toUpperCase()+after.slice(1));
+  }else{
+     return str.replace(before,after);
+  }
+
+}
+
+myReplace("He is Sleeping on the couch", "Sleeping", "sitting");
diff --git a/algorithm_FreeCodeCamp/slasher_Flick.js b/algorithm_FreeCodeCamp/slasher_Flick.js
new file mode 100644
index 0000000..215a65e
--- /dev/null
+++ b/algorithm_FreeCodeCamp/slasher_Flick.js
@@ -0,0 +1,4 @@
+function slasher(arr, howMany) {
+  return arr.slice(howMany);
+}
+slasher([1, 2, 3], 2);
\ No newline at end of file
diff --git a/algorithm_FreeCodeCamp/smallest_Common_Multiple.js b/algorithm_FreeCodeCamp/smallest_Common_Multiple.js
new file mode 100644
index 0000000..012657f
--- /dev/null
+++ b/algorithm_FreeCodeCamp/smallest_Common_Multiple.js
@@ -0,0 +1,23 @@
+function smallestCommons(arr) {
+  var range = [];
+  for (var i = Math.max(arr[0], arr[1]); i >= Math.min(arr[0], arr[1]); i--) {
+      range.push(i);
+    } 
+  
+  var lcm = range[0];
+  for (var i = 1; i<range.length; i++){
+    lcm = range[i]*lcm / gcd(lcm,range[i]);
+  }
+  return lcm; 
+}
+
+function gcd(a,b){
+    if (!b) {
+        return a;
+    }
+    return gcd(b, a % b);
+}
+
+
+
+smallestCommons([1, 5]);
\ No newline at end of file
diff --git a/algorithm_FreeCodeCamp/spinal_Case.js b/algorithm_FreeCodeCamp/spinal_Case.js
new file mode 100644
index 0000000..b42ca57
--- /dev/null
+++ b/algorithm_FreeCodeCamp/spinal_Case.js
@@ -0,0 +1,15 @@
+function spinalCase(str) {
+	str = str.replace(/[^a-zA-Z0-9-]|[a-z][A-Z]/g, function(word) {
+    if (word.match(/[a-z][A-Z]/)) {
+        return word[0] + "-" + word[1];
+        } else {
+        return "-";
+        }
+  });
+  return str.replace(/[A-Z]/g, function(x){
+    return x.toLowerCase();
+  });
+}
+
+
+spinalCase('thisIsSpinalTap');
\ No newline at end of file
diff --git a/algorithm_FreeCodeCamp/steam_Roller.js b/algorithm_FreeCodeCamp/steam_Roller.js
new file mode 100644
index 0000000..99509c1
--- /dev/null
+++ b/algorithm_FreeCodeCamp/steam_Roller.js
@@ -0,0 +1,16 @@
+var  valueArr=[];
+
+function steamrollArray(arr){
+
+  for(var i=0; i<arr.length ; i++){
+      if(Array.isArray(arr[i])){
+      result = arr[i];
+      steamrollArray(result);
+   }else{
+     valueArr.push(arr[i]);
+   }
+  } 
+  return valueArr;
+}
+
+steamrollArray([1, {}, [3, [[4]]]]);
\ No newline at end of file
diff --git a/algorithm_FreeCodeCamp/sum_All_Number.js b/algorithm_FreeCodeCamp/sum_All_Number.js
new file mode 100644
index 0000000..81de607
--- /dev/null
+++ b/algorithm_FreeCodeCamp/sum_All_Number.js
@@ -0,0 +1,7 @@
+function sumAll(arr) {
+  var f = arr[0];
+  var e = arr[1];
+  return (f+e)*(Math.abs(f-e)+1)/2;
+}
+
+sumAll([1, 4]);
diff --git a/algorithm_FreeCodeCamp/sum_All_Prime.js b/algorithm_FreeCodeCamp/sum_All_Prime.js
new file mode 100644
index 0000000..2a90997
--- /dev/null
+++ b/algorithm_FreeCodeCamp/sum_All_Prime.js
@@ -0,0 +1,27 @@
+function sumPrimes(num) {
+  var sum = 0;
+  for(var n=2; n<=num; n++){
+    if(isPrimes(n)){
+      sum += n;
+    }
+  } 
+  return sum;
+} 
+
+
+
+function isPrimes(num){
+  if (num == 2){
+    return true;
+  }
+  else{
+    for (var i = 2; i<num; i++){
+      if(num%i==0){
+        return false;
+      }
+    } return true;
+  }
+}
+
+
+sumPrimes(13);
diff --git a/algorithm_FreeCodeCamp/symmetirc_Difference.js b/algorithm_FreeCodeCamp/symmetirc_Difference.js
new file mode 100644
index 0000000..75b75fd
--- /dev/null
+++ b/algorithm_FreeCodeCamp/symmetirc_Difference.js
@@ -0,0 +1,22 @@
+
+function sym(args) {
+  var arr= Array.from(arguments);
+  arr = arr.reduce(function(a,b){
+    var aNotB = a.filter(function(val){
+      return !b.includes(val);
+    });
+    
+    var bNotA = b.filter(function(val){
+      return !a.includes(val);
+
+    });
+    return aNotB.concat(bNotA);
+  });
+  
+  return arr.filter(function (el, i, arr) {
+	return arr.indexOf(el) === i;
+});
+
+}
+
+sym([1, 1, 2, 5], [2, 2, 3, 5], [3, 4, 5, 5]);
diff --git a/algorithm_FreeCodeCamp/title_Case_a_Sentence.js b/algorithm_FreeCodeCamp/title_Case_a_Sentence.js
new file mode 100644
index 0000000..51c5e1e
--- /dev/null
+++ b/algorithm_FreeCodeCamp/title_Case_a_Sentence.js
@@ -0,0 +1,12 @@
+function titleCase(str) {
+  var newStr =  str.toLowerCase().split(" ");
+  result = [];
+  for (var i=0; i<newStr.length; i++){
+     Up = newStr[i][0].toUpperCase();
+     result.push(Up + newStr[i].slice(1));
+  }
+  
+  return result.join(" ");
+}
+
+titleCase("I'm a little tea pot");
\ No newline at end of file
diff --git a/algorithm_FreeCodeCamp/truncate_Strings.js b/algorithm_FreeCodeCamp/truncate_Strings.js
new file mode 100644
index 0000000..3e09c83
--- /dev/null
+++ b/algorithm_FreeCodeCamp/truncate_Strings.js
@@ -0,0 +1,12 @@
+function truncateString(str, num) {
+  if(num<=3){
+    return str.slice(0,num)+"...";
+  } else if(num < str.length){
+  return str.slice(0,num-3)+"...";
+  } else{
+    return str;
+  }
+}
+
+truncateString("A-tisket a-tasket A green and yellow basket", 11);
+
diff --git a/algorithm_FreeCodeCamp/validate_US_Telephone_Num.js b/algorithm_FreeCodeCamp/validate_US_Telephone_Num.js
new file mode 100644
index 0000000..481677a
--- /dev/null
+++ b/algorithm_FreeCodeCamp/validate_US_Telephone_Num.js
@@ -0,0 +1,8 @@
+function telephoneCheck(str) {
+  var regex= /^(1\s?)?(\(\d{3}\)|\d{3})[\s\-]?\d{3}[\s\-]?\d{4}$/;
+  return regex.test(str);
+}
+
+
+
+telephoneCheck("555-555-5555");
\ No newline at end of file