diff --git a/index.js b/index.js
index 0f4b28b..7decd6d 100644
--- a/index.js
+++ b/index.js
@@ -1,17 +1,62 @@
 class SortedList {
-  constructor() {}
+  constructor() {
+    this.items = [];
+    this.length = 0;
+}
+
+  add(item) 
+  {
+    // Add the item and keep the list sorted
+    this.items.push(item);
+    this.items.sort((a, b) => a - b);
+    // Update the length
+    this.length = this.items.length;
+  }
+
+
+  get(pos) {
+    // Check if pos is out of bounds
+    if (pos < 0 || pos >= this.length) {
+      throw new Error('OutOfBounds');
+    }
+    return this.items[pos];
+  }
+
+  max() {
+    // If the list is empty, throw an error
+    if (this.length === 0) {
 
-  add(item) {}
+      throw new Error('EmptySortedList');
+    }
+    // Return the last element (highest value since it's sorted)
+    return this.items[this.length - 1];
+  }
 
-  get(pos) {}
+  min() {
+    // If the list is empty, throw an error
+    if (this.length === 0) {
+      throw new Error('EmptySortedList');
+    }
+    // Return the first element (lowest value since it's sorted)
+    return this.items[0];
+  }
 
-  max() {}
 
-  min() {}
+  sum() {
+    // Calculate the sum using reduce
+    return this.items.reduce((acc, curr) => acc + curr, 0);
+  }
 
-  sum() {}
+  avg()
+   {
+    // If the list is empty, throw an error
+    if (this.length === 0) {
+      throw new Error('EmptySortedList');
+    }
 
-  avg() {}
+    // Return the average by dividing the sum by the length
+    return this.sum() / this.length;
+  }
 }
 
 module.exports = SortedList;
diff --git a/package.json b/package.json
index 2940292..9ade1c8 100644
--- a/package.json
+++ b/package.json
@@ -12,5 +12,8 @@
     "intro"
   ],
   "author": "supoort@rootlearn.com",
-  "license": "MIT"
+  "license": "MIT",
+  "dependencies": {
+    "mocha": "^10.8.2"
+  }
 }