diff --git a/03-index-slice-subset.md b/03-index-slice-subset.md
index 52a85a14e..c9576e6e7 100644
--- a/03-index-slice-subset.md
+++ b/03-index-slice-subset.md
@@ -283,9 +283,13 @@ surveys_df = pd.read_csv("data/surveys.csv")
 We can select specific ranges of our data in both the row and column directions
 using either label or integer-based indexing.
 
-- `loc` is primarily *label* based indexing. *Integers* may be used but
-  they are interpreted as a *label*.
-- `iloc` is primarily *integer* based indexing
+- `iloc` is primarily an *integer* based indexing counting from 0. That is, your
+  specify rows and columns giving a number. Thus, the first row is row 0,
+  the second column is column 1, etc.
+
+- `loc` is primarily a *label* based indexing where you can refer to rows and
+  columns by their name. E.g., column 'month'. Note that *integers* may be
+  used, but they are interpreted as a *label*.
 
 To select a subset of rows **and** columns from our DataFrame, we can use the
 `iloc` method. For example, we can select month, day and year (columns 2, 3
diff --git a/fig/00_0_jupyter_notebook_example.jpg b/fig/00_0_jupyter_notebook_example.jpg
old mode 100755
new mode 100644
diff --git a/md5sum.txt b/md5sum.txt
index e2c1d066e..76504c2fe 100644
--- a/md5sum.txt
+++ b/md5sum.txt
@@ -7,7 +7,7 @@
 "episodes/00-before-we-start.md" "0fbbeb717a3a6b613ff472b21bba4e21" "site/built/00-before-we-start.md" "2023-05-08"
 "episodes/01-short-introduction-to-Python.md" "8cdcf74a840b265b88ab60724ad17408" "site/built/01-short-introduction-to-Python.md" "2023-05-08"
 "episodes/02-starting-with-data.md" "4cac8c55b79e5e0f00a98880da127748" "site/built/02-starting-with-data.md" "2023-05-08"
-"episodes/03-index-slice-subset.md" "4005ea5fbee932f02a74e1e6db1120dd" "site/built/03-index-slice-subset.md" "2023-05-08"
+"episodes/03-index-slice-subset.md" "e0492e2a4d0e1a4a3a7bff0268f9b252" "site/built/03-index-slice-subset.md" "2023-05-15"
 "episodes/04-data-types-and-format.md" "04fae7c4573d1524b12f0977973151b9" "site/built/04-data-types-and-format.md" "2023-05-08"
 "episodes/05-merging-data.md" "3f14de8cbf7239389ba6110ff02523aa" "site/built/05-merging-data.md" "2023-05-08"
 "episodes/06-loops-and-functions.md" "812bd4379a6eca318cfee1ec976f946b" "site/built/06-loops-and-functions.md" "2023-05-08"