diff --git a/01 - Getting Started.ipynb b/01 - Getting Started.ipynb
index 33cebd9..f7d4ff1 100644
--- a/01 - Getting Started.ipynb	
+++ b/01 - Getting Started.ipynb	
@@ -947,18 +947,28 @@
         "### Exercise 4\n",
         "\n",
         "Add a new column to the `penguins` table with the mean mass of penguins found\n",
-        "on that island.\n",
-        "\n",
-        "```python\n",
+        "on that island."
+      ]
+    },
+    {
+      "cell_type": "code",
+      "metadata": {},
+      "source": [
         "mean_mass_per_island = (\n",
         "    penguins\n",
         "    .group_by(\"island\")\n",
         "    .agg(island_mean_mass=penguins.body_mass_g.mean())\n",
         ")\n",
         "\n",
-        "penguins.join(...)  # what goes here?\n",
-        "```\n",
-        "\n",
+        "penguins.join(...)  # what goes here?"
+      ],
+      "execution_count": null,
+      "outputs": []
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
         "#### Solution"
       ]
     },
diff --git a/03 - Switching Backends.ipynb b/03 - Switching Backends.ipynb
index 69b3c97..f279156 100644
--- a/03 - Switching Backends.ipynb	
+++ b/03 - Switching Backends.ipynb	
@@ -75,7 +75,9 @@
       "source": [
         "basics = con.read_parquet(\n",
         "    \"data/imdb/imdb_title_basics_sample_5.parquet\", table_name=\"imdb_title_basics\"\n",
-        ")"
+        ")\n",
+        "\n",
+        "basics"
       ],
       "execution_count": null,
       "outputs": []
@@ -86,7 +88,9 @@
       "source": [
         "ratings = con.read_parquet(\n",
         "    \"data/imdb/imdb_title_ratings.parquet\", table_name=\"imdb_title_ratings\"\n",
-        ")"
+        ")\n",
+        "\n",
+        "ratings"
       ],
       "execution_count": null,
       "outputs": []
diff --git a/quarto/01 - Getting Started.qmd b/quarto/01 - Getting Started.qmd
index b601ecf..abebeea 100644
--- a/quarto/01 - Getting Started.qmd	
+++ b/quarto/01 - Getting Started.qmd	
@@ -493,7 +493,7 @@ left.join(right, "key_column_name")
 Add a new column to the `penguins` table with the mean mass of penguins found
 on that island.
 
-```python
+```{python}
 mean_mass_per_island = (
     penguins
     .group_by("island")
diff --git a/quarto/03 - Switching Backends.qmd b/quarto/03 - Switching Backends.qmd
index 2d2a254..89edab5 100644
--- a/quarto/03 - Switching Backends.qmd	
+++ b/quarto/03 - Switching Backends.qmd	
@@ -51,12 +51,16 @@ con = ibis.duckdb.connect()
 basics = con.read_parquet(
     "data/imdb/imdb_title_basics_sample_5.parquet", table_name="imdb_title_basics"
 )
+
+basics
 ```
 
 ```{python}
 ratings = con.read_parquet(
     "data/imdb/imdb_title_ratings.parquet", table_name="imdb_title_ratings"
 )
+
+ratings
 ```
 
 ## Exercises
diff --git a/solutions/nb01_ex04.py b/solutions/nb01_ex04.py
index fd8cec0..0d270b8 100644
--- a/solutions/nb01_ex04.py
+++ b/solutions/nb01_ex04.py
@@ -1,6 +1,7 @@
-(
+mean_mass_per_island = (
     penguins
     .group_by("island")
     .agg(island_mean_mass=penguins.body_mass_g.mean())
-    .join(penguins, "island")
 )
+
+penguins.join(mean_mass_per_island, "island")