diff --git a/index.js b/index.js
index 0f4b28b..af4a571 100644
--- a/index.js
+++ b/index.js
@@ -1,17 +1,48 @@
 class SortedList {
-  constructor() {}
+  constructor() {
+    this.items = []
+    this.length = 0
+  }
 
-  add(item) {}
+  add(item) {
+    this.items.push(item)
+    this.length++
+    this.items.sort((a, b) => a - b)
+  }
 
-  get(pos) {}
+  get(pos) {
+    if (pos < this.length){
+      return this.items[pos]
+    }
+    throw new Error('OutOfBounds')
+  }
 
-  max() {}
+  max() {
+    if (this.length === 0){
+      throw new Error('EmptySortedList')
+    }
+    return this.items[this.length - 1]
+  }
 
-  min() {}
+  min() {
+    if (this.length === 0){
+      throw new Error('EmptySortedList')
+    }
+    return this.items[0]
+  }
 
-  sum() {}
+  sum() {
+    return this.items.reduce((sum, curr) => 
+      curr + sum, 0
+    )
+    }
 
-  avg() {}
+  avg() {
+    if (this.length === 0){
+      throw new Error('EmptySortedList')
+    }   
+    return this.sum() / this.length
+  }
 }
 
 module.exports = SortedList;
diff --git a/package.json b/package.json
index 2940292..2241c4d 100644
--- a/package.json
+++ b/package.json
@@ -12,5 +12,8 @@
     "intro"
   ],
   "author": "supoort@rootlearn.com",
-  "license": "MIT"
+  "license": "MIT",
+  "dependencies": {
+    "mocha": "^11.1.0"
+  }
 }