done

01/app.js

@@ -0,0 +1,4 @@
+const users = ['Maria Kaczyńska', 'Jarosław Boberek', 'Danuta kołaczkowska', 'Mariusz Pudzianowski', 'Bolesław Leśmian']; 
+
+console.log(users[0], '+', users[2], '+', users[4]);
+console.log(users.length);

02/app.js

@@ -1,6 +1,17 @@
 const randomArray = createRandomArray();
 console.log(randomArray);
+const lastIndex = randomArray.length -1;
 
+for(let i=0; i<randomArray.length; i++) {
+    console.log(randomArray[i]);
+}
+
+randomArray.forEach(function(element) {
+    console.log(element);
+});
+
+
+console.log(randomArray[lastIndex]);
 
 
 // nie modyfikuj kodu poniżej!

03/app.js

@@ -1,2 +1,11 @@
-const n = 24;
-const oddNumbers = [];
+const n = 55;
+const oddNumbers = [];
+
+
+for (let i=1; i<=n; i++) {
+    if(i % 2 !== 0) {
+        oddNumbers.push(i);
+    }
+}
+
+console.log(oddNumbers);

04/app.js

@@ -1 +1,5 @@
-const years = [1980, 1934, 2002, 2019];
+const years = [1980, 1934, 2002, 2019];
+const currentYear = 2021;
+const yearsAgo = years.map( year => currentYear - year );
+
+console.log(yearsAgo);

05/app.js

@@ -1 +1,12 @@
-const numbers = [1, 2, 3, 4, 5, 6, 7];
+const numbers = [1, 2, 3, 4, 5, 6, 7];
+
+
+const evenNumbers = numbers.filter(function(value) {
+    return value % 2 === 0;
+});
+
+const sumEvenNumbers = evenNumbers.reduce((accumulator, currentValue) => {
+    return accumulator + currentValue;
+}, 0);
+
+console.log(sumEvenNumbers);