diff --git a/.ipynb_checkpoints/3. NumPy exercises-checkpoint.ipynb b/.ipynb_checkpoints/3. NumPy exercises-checkpoint.ipynb
index 5c1a626..677401b 100644
--- a/.ipynb_checkpoints/3. NumPy exercises-checkpoint.ipynb	
+++ b/.ipynb_checkpoints/3. NumPy exercises-checkpoint.ipynb	
@@ -1021,7 +1021,7 @@
     "    [13, 14, 15, 16]\n",
     "])\n",
     "\n",
-    "X[2:, 2:]"
+    "X[-2:, -2:]"
    ]
   },
   {
@@ -1735,9 +1735,9 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.4"
+   "version": "3.8.5"
   }
  },
  "nbformat": 4,
- "nbformat_minor": 2
+ "nbformat_minor": 4
 }
diff --git a/3. NumPy exercises.ipynb b/3. NumPy exercises.ipynb
index deff2a9..677401b 100644
--- a/3. NumPy exercises.ipynb	
+++ b/3. NumPy exercises.ipynb	
@@ -1021,7 +1021,7 @@
     "    [13, 14, 15, 16]\n",
     "])\n",
     "\n",
-    "X[2:, 2:]"
+    "X[-2:, -2:]"
    ]
   },
   {
@@ -1735,7 +1735,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.8.1"
+   "version": "3.8.5"
   }
  },
  "nbformat": 4,