diff --git a/assets/array-methods-exercises.js b/assets/array-methods-exercises.js
new file mode 100644
index 000000000..29e0adc9a
--- /dev/null
+++ b/assets/array-methods-exercises.js
@@ -0,0 +1,22 @@
+const flowers = [
+  { name: 'tulip', color: 'red' },
+  { name: 'dandelion', color: 'yellow' },
+  { name: 'rose', color: 'red' },
+  { name: 'daisy', color: 'white' },
+  { name: 'lily', color: 'white' },
+];
+
+// Exercise 1
+// use `map` to make the first letter of al flowers a capital.
+// so 'tulip' becomes 'Tulip' etc.
+
+// Exercise 2
+// use `filter` to get only the flowers with a name of 4 characters
+
+// Exercise 3
+// use `reduce` to create an object that contains
+// the total number of flowers for each color
+
+// Exercise 4 (bonus)
+// use `some` or `every` in combination with another array method
+// to find out if all flowers with five letters are red
diff --git a/assets/sync-async.js b/assets/sync-async.js
new file mode 100644
index 000000000..8ccda654d
--- /dev/null
+++ b/assets/sync-async.js
@@ -0,0 +1,80 @@
+const greenGrocer = {
+  buyApples: function(quantity) {
+    return quantity + ' apples';
+  },
+  buyTomatoes: function(quantity) {
+    return quantity + ' tomatoes';
+  },
+  buyCauliflower: function(quantity) {
+    return quantity + ' cauliflower';
+  },
+};
+
+const cheeseShop = {
+  buyCheese: function(type, weight) {
+    this.cutCheese(type, weight);
+
+    return weight + 'gr ' + type + ' cheese';
+  },
+
+  cutCheese: function(type, weight) {
+    const stopTime = Date.now() + 100;
+    while (Date.now() < stopTime);
+  },
+};
+
+const bakery = {
+  buyBread: function(breadReadyCallback, type, quantity) {
+    setTimeout(function() {
+      breadReadyCallback(quantity + ' ' + type);
+    }, 1000);
+  },
+};
+
+function visitGreengrocer() {
+  console.log('=== Greengrocer ===');
+
+  const beforeBuy = Date.now();
+
+  const fruitsAndVegetables = [
+    greenGrocer.buyApples(2),
+    greenGrocer.buyTomatoes(2),
+    greenGrocer.buyCauliflower(1),
+  ];
+
+  const timeTaken = (Date.now() - beforeBuy).toFixed(2);
+
+  console.log('You bought: ', fruitsAndVegetables);
+  console.log('This took: ' + timeTaken + 'ms\n');
+}
+
+function visitCheeseShop() {
+  console.log('=== Cheese Shop ===');
+  const beforeBuy = Date.now();
+
+  const cheese = cheeseShop.buyCheese('belegen', 500);
+
+  const timeTaken = (Date.now() - beforeBuy).toFixed(2);
+
+  console.log('You bought: ' + cheese + '');
+  console.log('This took: ' + timeTaken + 'ms\n');
+}
+
+function visitBakery() {
+  console.log('=== Bakery ===');
+  const beforeBuy = Date.now();
+
+  const breadReady = function(bread) {
+    const timeTaken = (Date.now() - beforeBuy).toFixed(2);
+    console.log('--- Callback from Bakery ---');
+    console.log('You bought: ' + bread + '');
+    console.log('This took: ' + timeTaken + 'ms\n');
+  };
+
+  bakery.buyBread(breadReady, 'fijn volkoren', 1);
+  console.log(`We'll call you back!\n`);
+}
+
+visitGreengrocer(); // ?.
+visitBakery(); // ?.
+visitCheeseShop(); // ?.