diff --git a/fundamentals/03.1_computation_with_xarray.ipynb b/fundamentals/03.1_computation_with_xarray.ipynb
index 9dbaadd0..b72d93e9 100644
--- a/fundamentals/03.1_computation_with_xarray.ipynb
+++ b/fundamentals/03.1_computation_with_xarray.ipynb
@@ -149,7 +149,7 @@
    },
    "outputs": [],
    "source": [
-    "np.nan_to_num(ds.sst, 0)"
+    "np.nan_to_num(ds.sst, nan=0)"
    ]
   },
   {
@@ -167,7 +167,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "xr.apply_ufunc(np.nan_to_num, ds.sst, 0)"
+    "xr.apply_ufunc(np.nan_to_num, ds.sst, kwargs={\"nan\": 0})"
    ]
   },
   {