diff --git a/.eslintrc b/.eslintrc
new file mode 100644
index 0000000..e69de29
diff --git a/chapter04.js b/chapter04.js
index 12f6ef0..a3be62c 100644
--- a/chapter04.js
+++ b/chapter04.js
@@ -9,42 +9,109 @@
 
 // Problem 1: The sum of a range
 function range(start, end, step=1) {
-  // Your code here
+    if (step == 0) {
+        step = 1;
+    }
+    let arr = [];
+    if (step >=1) {
+        for(let i=start; i<=end; i+=step)
+            arr.push(i);
+    }
+    else {
+        for(let i=start; i>=end; i+=step)
+            arr.push(i);
+    }
+    return arr;
 }
 
 function sum(array) {
-  // Your code here
+    let sum = 0;
+    for(let i=0; i<array.length; i++)
+        sum += array[i]
+    return sum;
 }
 
 // Problem 2: Reversing an Array
 function reverseArray(array) {
-  // Your code here
+    let reversed = [];
+    let last = array.length - 1
+    for(let i = last; i >= 0; i--) { 
+        reversed.push(array[i]);
+    }
+    return reversed;
 }
 
 function reverseArrayInPlace(array) {
-  // Your code here
+    let mid = array.length / 2;
+    for(let i=0; i<=mid; i++){
+        let temp = array[i];
+        let opp_index = array.length-1-i;
+        array[i] = array[opp_index];
+        array[opp_index] = temp;
+    }
+    return array;
 }
 
 // Problem 3: A List
 function arrayToList(array) {
-  // Your code here
+    let list = null;
+    for(let i=array.length-1; i>=0; i--){
+        list = prepend(array[i], list)
+    }
+    return list;
 }
 
 function listToArray(list) {
-  // Your code here
+    let arr = [];
+    for(let node=list; node; node=node.rest) {
+        arr.push(node.value);
+    }
+    return arr;
 }
 
 function nth(list, position) {
-  // Your code here
+    let count = 0;
+    for(let node=list; node; node=node.rest) {
+        if(count == position)
+            return node.value;
+        count ++;
+    }
+    return undefined;
 }
 
 function prepend(element, list) {
-  // Your code here
+    let new_list = {
+        'value': element,
+        'rest': list
+    }
+    return new_list;
 }
 
 // Problem 4: Deep comparison
 function deepEqual(obj1, obj2) {
-  // Your code here
+    //Check if identical
+    if (obj1 === obj2) {
+        return true;
+    }
+
+    //Check type and nulls
+    if (obj1 == null || obj2 == null || typeof(obj1) != "object" || typeof(obj2) != "object") {
+        return false;
+    }
+
+    //Check length
+    if (Object.keys(obj1).length != Object.keys(obj2).length) {
+        return false;
+    }
+    //Deep comparison
+    for(item in obj1) {
+        if (obj2.hasOwnProperty(item)) {
+            if ( !(deepEqual(obj1[item], obj2[item]))) {
+                return false;
+            }
+        }
+    }
+    return true;
 }
 
 
diff --git a/chapter05.js b/chapter05.js
index d1372cb..5f61852 100644
--- a/chapter05.js
+++ b/chapter05.js
@@ -8,25 +8,32 @@
 const ancestry = require('./ancestry');
 
 function average(array) {
-  function plus(a, b) { return a + b; }
-  return array.reduce(plus) / array.length;
+	function plus(a, b) { return a + b; }
+	return array.reduce(plus) / array.length;
 }
 
 const byName = {};
-ancestry.forEach(function(person) {
-  byName[person.name] = person;
+ancestry.forEach((person) => {
+	byName[person.name] = person;
 });
 
 
 // Problem 1: Flattening
-function flatten(arrays) {
-  // Your code here
+function flatten(array) {
+	return array.reduce((flat_arr, curr_arr) => {
+		return flat_arr.concat(curr_arr);
+  }, [])
 }
 
 // Problem 2: Mother-child age difference
 /* This must return the average age difference instead of printing it */
 function averageMomChildAgeDiff() {
-  // Your code here
+	let differences = ancestry.filter((person) => {
+		return byName[person.mother] != null;   //filter those who only have mothers in data
+	}).map((person) => {
+		return person.born - byName[person.mother].born;
+	});
+	return average(differences);
 }
 
 // Problem 3: Historical life expectancy
@@ -34,7 +41,18 @@ function averageMomChildAgeDiff() {
     for the century as the value
  */
 function averageAgeByCentury() {
-  // Your code here
+  let centuryAges = {};
+  ancestry.forEach((person) => {
+	  let century = Math.ceil(person.died / 100);
+	  if (!(centuryAges.hasOwnProperty(century))) {
+		centuryAges[century] = [];
+	  }
+	  centuryAges[century].push(person.died-person.born);
+  });
+  for (century in centuryAges) {
+	  centuryAges[century] = average(centuryAges[century]);
+  }
+  return centuryAges;
 }
 
 
diff --git a/chapter13.js b/chapter13.js
index ab99bc6..95f104d 100644
--- a/chapter13.js
+++ b/chapter13.js
@@ -9,7 +9,28 @@
 
 // Problem 1: Build table
 function buildTable(data) {
-  // Your code here
+  let table = document.createElement("table");
+  let attributes = Object.keys(data[0]);
+  let top_row = document.createElement("tr");
+  for (attrib in attributes) {
+    let header_cell = document.createElement('th');
+    header_cell.textContent = attrib;
+    top_row.appendChild(header_cell);
+  }
+  table.appendChild(top_row);
+  data.forEach((obj) => {                 //Each mountain object
+    let table_row = document.createElement("tr");
+    attributes.forEach((attrib) => {              //Name, Height, Country values
+      let row_cell = document.createElement("td");
+      row_cell.textContent = obj[attrib];
+      if (typeof obj[attrib] == "number") {
+        row_cell.style.textAlign == "right";
+      }
+      table_row.appendChild(row_cell);      
+    });
+    table.appendChild(table_row);
+  });
+  return table;
 }