diff --git a/01_helloWorld/helloWorld.js b/01_helloWorld/helloWorld.js
index df27036..b542f3b 100644
--- a/01_helloWorld/helloWorld.js
+++ b/01_helloWorld/helloWorld.js
@@ -1,5 +1,5 @@
 const helloWorld = function() {
-  return ''
+  return 'Hello, World!'
 };
 
 module.exports = helloWorld;
diff --git a/02_repeatString/repeatString.js b/02_repeatString/repeatString.js
index 4359bbe..02bdac7 100644
--- a/02_repeatString/repeatString.js
+++ b/02_repeatString/repeatString.js
@@ -1,5 +1,13 @@
-const repeatString = function() {
-
+const repeatString = function(str,n) {
+    if(n<0)
+    return "ERROR"
+    let s="";
+    while(n)
+    {
+        s+=str;
+        n--;
+    }
+    return s;
 };
 
 // Do not edit below this line
diff --git a/03_reverseString/reverseString.js b/03_reverseString/reverseString.js
index f6790f0..e9bcf5e 100644
--- a/03_reverseString/reverseString.js
+++ b/03_reverseString/reverseString.js
@@ -1,5 +1,5 @@
-const reverseString = function() {
-
+const reverseString = function(str) {
+    return str.split("").reverse().join("");
 };
 
 // Do not edit below this line
diff --git a/04_removeFromArray/removeFromArray.js b/04_removeFromArray/removeFromArray.js
index 1bedeb0..4c7aba0 100644
--- a/04_removeFromArray/removeFromArray.js
+++ b/04_removeFromArray/removeFromArray.js
@@ -1,5 +1,13 @@
-const removeFromArray = function() {
-
+const removeFromArray = function(arr,...args) {
+    for(let arg of args)
+    {
+        let index=arr.indexOf(arg);
+        if(index>=0)
+        {
+            arr.splice(index,1);
+        }
+    }
+    return arr
 };
 
 // Do not edit below this line
diff --git a/05_sumAll/sumAll.js b/05_sumAll/sumAll.js
index 00880c7..c88fd64 100644
--- a/05_sumAll/sumAll.js
+++ b/05_sumAll/sumAll.js
@@ -1,4 +1,25 @@
-const sumAll = function() {
+const sumAll = function(s,e) {
+    if(typeof(s)==="number" && typeof(e)=="number" && s>=0 && e>=0)
+    {
+        let sum=0;
+        if(s<=e)
+        {
+            for(let i=s;i<=e;i++)
+              {
+                 sum+=i;
+            }
+        }
+        else
+        {
+            for(let i=s;i>=e;i--)
+              {
+                 sum+=i;
+            }
+        }
+        return sum;
+    }
+    else
+    return "ERROR"
 
 };
 
diff --git a/06_leapYears/leapYears.js b/06_leapYears/leapYears.js
index 681eeef..490d5eb 100644
--- a/06_leapYears/leapYears.js
+++ b/06_leapYears/leapYears.js
@@ -1,5 +1,8 @@
-const leapYears = function() {
-
+const leapYears = function(x) {
+    if ((x%4==0 && x%100) || (x%4==0 && x%100==0 && x%40==0))
+    return true;
+    else
+    return false;
 };
 
 // Do not edit below this line
diff --git a/07_tempConversion/tempConversion.js b/07_tempConversion/tempConversion.js
index 14153e0..0c5e9ce 100644
--- a/07_tempConversion/tempConversion.js
+++ b/07_tempConversion/tempConversion.js
@@ -1,7 +1,11 @@
-const convertToCelsius = function() {
+const convertToCelsius = function(x) {
+  let c=((x-32)*5)/9;
+  return Math.round(c*10)/10;
 };
 
-const convertToFahrenheit = function() {
+const convertToFahrenheit = function(x) {
+  let f=((x*9)/5)+32;
+  return Math.round(f*10)/10;
 };
 
 // Do not edit below this line
diff --git a/08_calculator/calculator.js b/08_calculator/calculator.js
index c22e8d2..921d0c9 100644
--- a/08_calculator/calculator.js
+++ b/08_calculator/calculator.js
@@ -1,25 +1,41 @@
-const add = function() {
-	
+const add = function(x,y) {
+	return x+y
 };
 
-const subtract = function() {
-	
+const subtract = function(x,y) {
+	return x-y
 };
 
-const sum = function() {
-	
+const sum = function(a) {
+	let s=parseInt(0);
+  for(let i=0;i<a.length;i++)
+  {
+    s+=parseInt(a[i]);
+  }
+  return s;
 };
 
-const multiply = function() {
-
+const multiply = function(a) {
+  let ans=1;
+  for(let i=0;i<a.length;i++)
+  {
+    ans*=a[i];
+  }
+  return ans;
 };
 
-const power = function() {
-	
+const power = function(x,y) {
+  return Math.pow(x,y)
 };
 
-const factorial = function() {
-	
+const factorial = function(x) {
+	let f=1;
+  while(x)
+  {
+    f*=x;
+    x--;
+  }
+  return f;
 };
 
 // Do not edit below this line
diff --git a/09_palindromes/palindromes.js b/09_palindromes/palindromes.js
index 8d21018..2a8375e 100644
--- a/09_palindromes/palindromes.js
+++ b/09_palindromes/palindromes.js
@@ -1,5 +1,24 @@
-const palindromes = function () {
-
+function checkIfLetter(s)
+{
+    return s.toLowerCase() != s.toUpperCase();
+}
+const palindromes = function (str) {
+    let s=0,e=str.length-1;
+    str=str.toLowerCase()
+    while(s<=e)
+    {
+        while(!checkIfLetter(str[s]))
+        {
+            s++;
+        }
+        while(!checkIfLetter(str[e]))
+        e--;
+        if(str[s]!=str[e])
+        return false;
+        s++;
+        e--;
+    }
+    return true;
 };
 
 // Do not edit below this line
diff --git a/10_fibonacci/fibonacci.js b/10_fibonacci/fibonacci.js
index bb2c8cc..5b2e916 100644
--- a/10_fibonacci/fibonacci.js
+++ b/10_fibonacci/fibonacci.js
@@ -1,5 +1,15 @@
-const fibonacci = function() {
-
+const fibonacci = function(n) {
+    if((n)<0)
+    return "OOPS";
+    let a=0,b=1,c;
+    while((n))
+    {
+        c=a+b;
+        a=b;
+        b=c;
+        n--;
+    }
+    return a;
 };
 
 // Do not edit below this line
diff --git a/11_getTheTitles/getTheTitles.js b/11_getTheTitles/getTheTitles.js
index 74b04df..8d40c27 100644
--- a/11_getTheTitles/getTheTitles.js
+++ b/11_getTheTitles/getTheTitles.js
@@ -1,5 +1,5 @@
-const getTheTitles = function() {
-
+const getTheTitles = function(obj) {
+return obj.map((x)=>x.title)
 };
 
 // Do not edit below this line
diff --git a/12_findTheOldest/findTheOldest.js b/12_findTheOldest/findTheOldest.js
index 366856a..87706ea 100644
--- a/12_findTheOldest/findTheOldest.js
+++ b/12_findTheOldest/findTheOldest.js
@@ -1,5 +1,14 @@
-const findTheOldest = function() {
-
+const findTheOldest = function(obj) {
+    return obj.reduce((acc,curr)=>{
+         let birthCurr=curr.yearOfBirth
+        let deathCurr=("yearOfDeath" in curr)?curr.yearOfDeath:(new Date().getFullYear());
+        let diffCurr=(deathCurr-birthCurr)
+        let birthAcc=acc.yearOfBirth
+        let deathAcc=("yearOfDeath" in acc)?acc.yearOfDeath:(new Date().getFullYear());
+        let diffAcc=(deathAcc-birthAcc) 
+        acc=(diffCurr>diffAcc)?curr:acc;
+        return acc;
+    })
 };
 
 // Do not edit below this line