diff --git a/index.js b/index.js
index 0f4b28b4..dfe8015d 100644
--- a/index.js
+++ b/index.js
@@ -1,17 +1,55 @@
 class SortedList {
-  constructor() {}
+  constructor() {
+    this.items = [];
+    this.length = 0;
+  }
 
-  add(item) {}
+  add(item) {
+    this.items.push(item);
+    this.items.sort((a, b) => a - b);
+    this.length = this.items.length;
+  }
 
-  get(pos) {}
+  get(pos) {
+  if (this.items[pos] === undefined) {
+    throw new Error("OutOfBounds");
+  }
+  return this.items[pos];
+}
+  }
+
+  max() {
+  if (this.length === 0) {
+    throw new Error("Empty SortedList");
+  }
+  return this.items[this.items.length - 1];
+}
+  
 
-  max() {}
+  min() {
+     if (this.length === 0) {
+    throw new Error("EmptySortedList");
+  }
+  return this.items[0];
+  }
 
-  min() {}
+  sum() {
+      let total = 0;
 
-  sum() {}
+  for (let i = 0; i < this.items.length; i++) {
+    total = total + this.items[i];
+  }
+
+  return total;
+  }
+
+  avg() {
+     if (this.length === 0) {
+    throw new Error("EmptySortedList");
+  }
+
+  return this.sum() / this.length;
+  }
 
-  avg() {}
-}
 
 module.exports = SortedList;
diff --git a/package.json b/package.json
index 3a5127ae..f2ff4434 100644
--- a/package.json
+++ b/package.json
@@ -19,5 +19,8 @@
     "intro"
   ],
   "author": "fer@ironhack.com",
-  "license": "MIT"
+  "license": "MIT",
+  "dependencies": {
+    "mocha": "^11.7.5"
+  }
 }