diff --git a/_config.yml b/_config.yml
index 00ef7d47..c2009490 100644
--- a/_config.yml
+++ b/_config.yml
@@ -60,3 +60,6 @@ bibtex_bibfiles:
 sphinx:
   config:
     bibtex_reference_style: author_year # or label, super, \supercite
+  extra_extensions:
+    - sphinx_exercise
+    - sphinx_togglebutton
diff --git a/conda/environment-unpinned.yml b/conda/environment-unpinned.yml
index debfa290..c4c36824 100644
--- a/conda/environment-unpinned.yml
+++ b/conda/environment-unpinned.yml
@@ -21,6 +21,7 @@ dependencies:
   - hvplot
   - matplotlib-base
   - netcdf4
+  - pip
   - pint-xarray
   - pydap
   - python-graphviz
@@ -29,3 +30,5 @@ dependencies:
   - scipy
   - xarray
   - zarr
+  - pip:
+      - sphinx-exercise
diff --git a/fundamentals/02.3_aligning_data_objects.ipynb b/fundamentals/02.3_aligning_data_objects.ipynb
index ba1c3a6b..e59a2772 100644
--- a/fundamentals/02.3_aligning_data_objects.ipynb
+++ b/fundamentals/02.3_aligning_data_objects.ipynb
@@ -377,9 +377,15 @@
   },
   {
    "cell_type": "markdown",
-   "metadata": {},
+   "metadata": {
+    "tags": []
+   },
    "source": [
-    "**Exercise**  Consider the following two arrays. Write down the `x` and `y` coordinate locations for `da1 - da2`"
+    "```{exercise-start}\n",
+    ":label: exercise-alignment\n",
+    "\n",
+    "Consider the following two arrays. Write down the `x` and `y` coordinate locations for `da1 - da2`\n",
+    "```"
    ]
   },
   {
@@ -388,6 +394,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
+    "# This code cell is executed by jupyterbook\n",
     "da1 = xr.DataArray(\n",
     "    np.arange(12).reshape(3, 4),\n",
     "    dims=(\"x\", \"y\"),\n",
@@ -408,7 +415,15 @@
     ]
    },
    "source": [
-    "**Answer** `x = [\"b\"], y=[0, 1, 2, 3]` . `da2` has been broadcasted to 2D  (so dimension \"y\" has been inserted) and the two arrays are aligned using `join=\"inner\"` prior to subtraction."
+    "```{exercise-end}\n",
+    "```\n",
+    "\n",
+    "```{solution} exercise-alignment\n",
+    ":label: solution-alignment\n",
+    ":class: dropdown\n",
+    "\n",
+    "`x = [\"b\"], y=[0, 1, 2, 3]` . `da2` has been broadcasted to 2D  (so dimension \"y\" has been inserted) and the two arrays are aligned using `join=\"inner\"` prior to subtraction.\n",
+    "```"
    ]
   },
   {
@@ -510,7 +525,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.9.12"
+   "version": "3.10.5"
   },
   "widgets": {
    "application/vnd.jupyter.widget-state+json": {