diff --git a/checks/itertools/itertools3.py b/checks/itertools/itertools3.py
index 629c89d..9bc38e6 100644
--- a/checks/itertools/itertools3.py
+++ b/checks/itertools/itertools3.py
@@ -1,2 +1,2 @@
-assert coordinates == [(0, "low"), (0, "high"), (1, "low"), (1, "high")]
+assert coordinates == [(0, "low"), (0, "high"), (1, "low"), (1, "high")], f"Expected [(0, 'low'), (0, 'high'), (1, 'low'), (1, 'high')], got {coordinates}"
 print("itertools3 ok")
diff --git a/checks/itertools/itertools4.py b/checks/itertools/itertools4.py
index 858745e..7614549 100644
--- a/checks/itertools/itertools4.py
+++ b/checks/itertools/itertools4.py
@@ -1,2 +1,2 @@
-assert grouped == {"fruit": ["apple", "pear"], "veg": ["carrot"]}
+assert grouped == {"fruit": ["apple", "pear"], "veg": ["carrot"]}, f"Expected {{'fruit': ['apple', 'pear'], 'veg': ['carrot']}}, got {grouped}"
 print("itertools4 ok")
diff --git a/checks/itertools/itertools5.py b/checks/itertools/itertools5.py
index de89c34..37d7594 100644
--- a/checks/itertools/itertools5.py
+++ b/checks/itertools/itertools5.py
@@ -1,2 +1,2 @@
-assert running_totals == [3, 7, 12, 18]
+assert running_totals == [3, 7, 12, 18], f"Expected [3, 7, 12, 18], got {running_totals}"
 print("itertools5 ok")
diff --git a/checks/itertools/itertools6.py b/checks/itertools/itertools6.py
index ffb0e86..c32e1d1 100644
--- a/checks/itertools/itertools6.py
+++ b/checks/itertools/itertools6.py
@@ -1,2 +1,2 @@
-assert repeated == ["red", "blue", "red", "blue", "red", "blue"]
+assert repeated == ["red", "blue", "red", "blue", "red", "blue"], f"Expected ['red', 'blue', 'red', 'blue', 'red', 'blue'], got {repeated}"
 print("itertools6 ok")
diff --git a/checks/itertools/itertools7.py b/checks/itertools/itertools7.py
index 6a3219b..45b7123 100644
--- a/checks/itertools/itertools7.py
+++ b/checks/itertools/itertools7.py
@@ -1,2 +1,2 @@
-assert pairs == [("a", 1), ("b", "?"), ("c", "?")]
+assert pairs == [("a", 1), ("b", "?"), ("c", "?")], f"Expected [('a', 1), ('b', '?'), ('c', '?')], got {pairs}"
 print("itertools7 ok")
diff --git a/checks/itertools/itertools8.py b/checks/itertools/itertools8.py
index e188cba..8925173 100644
--- a/checks/itertools/itertools8.py
+++ b/checks/itertools/itertools8.py
@@ -1,3 +1,3 @@
-assert flattened == [1, 2, 3, 4, 5]
-assert adjacent_pairs == [(1, 2), (2, 3), (3, 4), (4, 5)]
+assert flattened == [1, 2, 3, 4, 5], f"Expected [1, 2, 3, 4, 5], got {flattened}"
+assert adjacent_pairs == [(1, 2), (2, 3), (3, 4), (4, 5)], f"Expected [(1, 2), (2, 3), (3, 4), (4, 5)], got {adjacent_pairs}"
 print("itertools8 ok")