diff --git a/01 - JavaScript Drum Kit/index-START.html b/01 - JavaScript Drum Kit/index-START.html
index 4070d32767..cfd5c98349 100644
--- a/01 - JavaScript Drum Kit/index-START.html	
+++ b/01 - JavaScript Drum Kit/index-START.html	
@@ -58,7 +58,25 @@
   <audio data-key="76" src="sounds/tink.wav"></audio>
 
 <script>
+  function playSound(e) {
+    const audio = document.querySelector(`audio[data-key="${e.keyCode}"`);
+    const key = document.querySelector(`.key[data-key="${e.keyCode}"`);
+    if (!audio) return; // stop if key has no sound
+    if (audio.currentTime > 0.02) {audio.currentTime = 0;} // rewind to start
+    audio.play();
+    key.classList.add('playing'); 
+  }
 
+  // to remove the scaling when the transition has ended
+  function removeTransition(e) {
+    if (e.propertyName !== 'transform') return; // just for the transform transition
+    this.classList.remove('playing');
+  }
+  
+  window.addEventListener('keydown', playSound);
+
+  const keys = document.querySelectorAll('.key')
+  keys.forEach(key => key.addEventListener('transitionend', removeTransition))
 </script>
 
 
diff --git a/04 - Array Cardio Day 1/index-START.html b/04 - Array Cardio Day 1/index-START.html
index 21bec96e8c..a9254b5afb 100644
--- a/04 - Array Cardio Day 1/index-START.html	
+++ b/04 - Array Cardio Day 1/index-START.html	
@@ -13,18 +13,18 @@
     // Some data we can work with
 
     const inventors = [
-      { first: 'Albert', last: 'Einstein', year: 1879, passed: 1955 },
-      { first: 'Isaac', last: 'Newton', year: 1643, passed: 1727 },
-      { first: 'Galileo', last: 'Galilei', year: 1564, passed: 1642 },
-      { first: 'Marie', last: 'Curie', year: 1867, passed: 1934 },
-      { first: 'Johannes', last: 'Kepler', year: 1571, passed: 1630 },
-      { first: 'Nicolaus', last: 'Copernicus', year: 1473, passed: 1543 },
-      { first: 'Max', last: 'Planck', year: 1858, passed: 1947 },
-      { first: 'Katherine', last: 'Blodgett', year: 1898, passed: 1979 },
-      { first: 'Ada', last: 'Lovelace', year: 1815, passed: 1852 },
-      { first: 'Sarah E.', last: 'Goode', year: 1855, passed: 1905 },
-      { first: 'Lise', last: 'Meitner', year: 1878, passed: 1968 },
-      { first: 'Hanna', last: 'Hammarström', year: 1829, passed: 1909 }
+      { first: 'Albert',    last: 'Einstein',     year: 1879, passed: 1955 },
+      { first: 'Isaac',     last: 'Newton',       year: 1643, passed: 1727 },
+      { first: 'Galileo',   last: 'Galilei',      year: 1564, passed: 1642 },
+      { first: 'Marie',     last: 'Curie',        year: 1867, passed: 1934 },
+      { first: 'Johannes',  last: 'Kepler',       year: 1571, passed: 1630 },
+      { first: 'Nicolaus',  last: 'Copernicus',   year: 1473, passed: 1543 },
+      { first: 'Max',       last: 'Planck',       year: 1858, passed: 1947 },
+      { first: 'Katherine', last: 'Blodgett',     year: 1898, passed: 1979 },
+      { first: 'Ada',       last: 'Lovelace',     year: 1815, passed: 1852 },
+      { first: 'Sarah E.',  last: 'Goode',        year: 1855, passed: 1905 },
+      { first: 'Lise',      last: 'Meitner',      year: 1878, passed: 1968 },
+      { first: 'Hanna',     last: 'Hammarström',  year: 1829, passed: 1909 }
     ];
 
     const people = [
@@ -37,29 +37,59 @@
     
     // Array.prototype.filter()
     // 1. Filter the list of inventors for those who were born in the 1500's
+    const old = inventors.filter(p => 1500 <= p.year && p.year < 1600);
+    console.table(old);
 
     // Array.prototype.map()
     // 2. Give us an array of the inventors first and last names
+    const names = inventors.map(p => `${p.first} ${p.last}`);
+    console.log(names);
 
     // Array.prototype.sort()
     // 3. Sort the inventors by birthdate, oldest to youngest
+    const sorted = inventors.sort((a,b) => a.year > b.year ? 1 : -1);
+    console.table(sorted);
 
     // Array.prototype.reduce()
     // 4. How many years did all the inventors live all together?
+    const sumAge = inventors.reduce((acc, a) => acc + a.passed - a.year, 0);
+    console.log(sumAge);
 
     // 5. Sort the inventors by years lived
-
+    const sorted2 = inventors.sort((a,b) => 
+          a.passed-a.year > b.passed-b.year ? -1 : 1);
+    console.table(sorted2);
+    
     // 6. create a list of Boulevards in Paris that contain 'de' anywhere in the name
     // https://en.wikipedia.org/wiki/Category:Boulevards_in_Paris
-
+    const links = Array.from(document.querySelectorAll('.mw-category a'));
+    const de = links
+                  .map(link => link.textContent)
+                  .filter(street => street.includes('de'));
 
     // 7. sort Exercise
     // Sort the people alphabetically by last name
+    const sorted3 = people.sort((a,b) => a > b ? 1 : -1);
+    console.table(sorted3);
+
+
+    const sorted4 = people.sort((a,b) => {
+      const [al, af] = a.split(', ');
+      const [bl, bf] = b.split(', ');
+      return al > bl ? 1: -1;
+    });
+  
 
     // 8. Reduce Exercise
     // Sum up the instances of each of these
     const data = ['car', 'car', 'truck', 'truck', 'bike', 'walk', 'car', 'van', 'bike', 'walk', 'car', 'van', 'car', 'truck' ];
-
+    const dataSum = data.reduce((acc, a) => {
+      if (!acc[a]) acc[a] = 0;
+      acc[a]++;
+      return acc;
+    },{});
+    console.log(dataSum);
+    
   </script>
 </body>
 </html>
diff --git a/07 - Array Cardio Day 2/index-START.html b/07 - Array Cardio Day 2/index-START.html
index 969566ff78..0fa5c967b2 100644
--- a/07 - Array Cardio Day 2/index-START.html	
+++ b/07 - Array Cardio Day 2/index-START.html	
@@ -26,15 +26,25 @@
 
     // Some and Every Checks
     // Array.prototype.some() // is at least one person 19 or older?
+    const someone = people.some(a => (new Date()).getFullYear() - a.year >= 19);
+    console.log(someone);
+    
     // Array.prototype.every() // is everyone 19 or older?
+    const everyone = people.every(a => (new Date()).getFullYear() - a.year >= 19);
+    console.log(everyone);
 
     // Array.prototype.find()
     // Find is like filter, but instead returns just the one you are looking for
     // find the comment with the ID of 823423
+    const theOne = comments.find(a => a.id === 823423);
+    console.log(theOne);
 
     // Array.prototype.findIndex()
     // Find the comment with this ID
     // delete the comment with the ID of 823423
+    const index = comments.findIndex(a => a.id === 823423);
+    comments.splice(index,1);
+    console.table(comments);
 
   </script>
 </body>
diff --git a/25 - Event Capture, Propagation, Bubbling and Once/index-START.html b/25 - Event Capture, Propagation, Bubbling and Once/index-START.html
index 7bd5931e01..b137f98db0 100644
--- a/25 - Event Capture, Propagation, Bubbling and Once/index-START.html	
+++ b/25 - Event Capture, Propagation, Bubbling and Once/index-START.html	
@@ -40,9 +40,21 @@
   }
 </style>
 
-<button></button>
+<button>.</button>
 <script>
 
+function logStuff(e) {
+    console.log(this.classList.value);
+    e.stopPropagation();
+  }
+
+  const divs = document.querySelectorAll('div');
+  divs.forEach(div => div.addEventListener('click', logStuff));
+
+  const button = document.querySelector('button');
+  button.addEventListener('click', e => console.log('click!!!'), {once: true});  
+
+
 </script>
 </body>
 </html>