diff --git a/04-arithmetic/mediana.js b/04-arithmetic/mediana.js
new file mode 100644
index 0000000..5c0cd1d
--- /dev/null
+++ b/04-arithmetic/mediana.js
@@ -0,0 +1,30 @@
+const NUMBERS = [100, 200, 500, 400000000];
+
+const calcularMediaAritmetica = (arr) =>
+ arr.reduce(
+ (valorAcumulado = 0, nuevoElemento) => valorAcumulado + nuevoElemento
+ ) / arr.length;
+
+const mitadLista1 = NUMBERS.length / 2;
+
+function isEven(n) {
+ if (!n % 2 === 0) {
+ return true;
+ }
+ return false;
+}
+
+let mediana;
+
+if (isEven(NUMBERS.length)) {
+ const elemento1 = NUMBERS[mitadLista1 - 1];
+ const elemento2 = NUMBERS[mitadLista1];
+
+ const promedioElemento1y2 = calcularMediaAritmetica([elemento1, elemento2]);
+
+ mediana = promedioElemento1y2;
+} else {
+ mediana = NUMBERS[mitadLista1];
+}
+
+console.log(mediana);
diff --git a/04-arithmetic/mode.js b/04-arithmetic/mode.js
new file mode 100644
index 0000000..7ca06e7
--- /dev/null
+++ b/04-arithmetic/mode.js
@@ -0,0 +1,11 @@
+const NUMBERS = [2, 2, 2, 2, 2, 4, 5, 5, 5, 5, 5, 5, 5, 5, 9];
+
+function mode(arr){
+ return arr.sort((a,b) =>
+ arr.filter(v => v===a).length
+ - arr.filter(v => v===b).length
+ ).pop();
+}
+
+
+console.log(mode(NUMBERS));
diff --git a/05-salary/analysis.js b/05-salary/analysis.js
new file mode 100644
index 0000000..92c88a3
--- /dev/null
+++ b/05-salary/analysis.js
@@ -0,0 +1,39 @@
+const esPar = (n) => n % 2 === 0;
+
+const calcularMediaAritmetica = (lista) =>
+ lista.reduce(
+ (valorAcumulado = 0, nuevoElemento) => valorAcumulado + nuevoElemento
+ ) / lista.length;
+
+function medianaSalarios(arr) {
+ const mitad = arr.length / 2;
+
+ if (esPar(arr.length)) {
+ const personitaMitad1 = arr[mitad - 1];
+ const personitaMitad2 = arr[mitad];
+
+ const mediana = calcularMediaAritmetica([personitaMitad1, personitaMitad2]);
+ return mediana;
+ }
+ return arr[mitad];
+}
+
+const salarios = colombia.map((personita) => personita.salary);
+
+const salariosColSorted = salarios.sort(
+ (salaryA, salaryB) => salaryA - salaryB
+);
+
+const medianaGeneral = medianaSalarios(salariosColSorted);
+
+const spliceStart = (salariosColSorted.length * 90) / 100;
+const spliceCount = salariosColSorted.length - spliceStart;
+
+const salaryTop10 = salariosColSorted.splice(spliceStart, spliceCount);
+
+const medianaTop10 = medianaSalarios(salaryTop10);
+
+console.log({
+ medianaGeneralCol: medianaGeneral,
+ medianaTop10Col: medianaTop10,
+});
diff --git a/05-salary/index.html b/05-salary/index.html
new file mode 100644
index 0000000..9c44e52
--- /dev/null
+++ b/05-salary/index.html
@@ -0,0 +1,17 @@
+
+
+
+
+
+
+
+
+ Salarios
+
+
+ Salarios
+
+
+
+
+
diff --git a/05-salary/persons.js b/05-salary/persons.js
new file mode 100644
index 0000000..47e8a69
--- /dev/null
+++ b/05-salary/persons.js
@@ -0,0 +1,81 @@
+const colombia = [];
+colombia.push({
+ name: 'Camila',
+ salary: 500,
+});
+colombia.push({
+ name: 'Nath',
+ salary: 1500,
+});
+colombia.push({
+ name: 'Luisa',
+ salary: 1800,
+});
+colombia.push({
+ name: 'Laura',
+ salary: 1000,
+});
+colombia.push({
+ name: 'Daniela',
+ salary: 2200,
+});
+colombia.push({
+ name: 'Esperancita',
+ salary: 200,
+});
+colombia.push({
+ name: 'Carla',
+ salary: 500,
+});
+colombia.push({
+ name: 'Antonieta',
+ salary: 1500,
+});
+colombia.push({
+ name: 'Alicia',
+ salary: 1300,
+});
+colombia.push({
+ name: 'Ana',
+ salary: 2400,
+});
+colombia.push({
+ name: 'Julia',
+ salary: 3400,
+});
+colombia.push({
+ name: 'Rosa',
+ salary: 400,
+});
+colombia.push({
+ name: 'Angélica',
+ salary: 400,
+});
+colombia.push({
+ name: 'Tatiana',
+ salary: 400,
+});
+colombia.push({
+ name: 'Lorena',
+ salary: 600,
+});
+colombia.push({
+ name: 'Carolina',
+ salary: 1600,
+});
+colombia.push({
+ name: 'Fernanda',
+ salary: 2600,
+});
+colombia.push({
+ name: 'Nora',
+ salary: 1000,
+});
+colombia.push({
+ name: 'Gisselle',
+ salary: 2000,
+});
+colombia.push({
+ name: 'Bill Gates',
+ salary: 100000000,
+});