diff --git a/foundations/09_sumAll/README.md b/foundations/09_sumAll/README.md
index 41026d40b5b..4bd7339b243 100644
--- a/foundations/09_sumAll/README.md
+++ b/foundations/09_sumAll/README.md
@@ -11,4 +11,8 @@ sumAll(1, 4) // returns the sum of 1 + 2 + 3 + 4 which is 10
 
 - How will you ensure you're summing all integers within the correct range, no matter the order of the inputs?
 
-- Think about your sum's starting value. Then, how can you make sure every single number from the smaller input to the larger one (including both) gets added to it?
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+- Think about your sum's starting value. Then, how can you make sure every single number from the smaller input to the larger one (including both) gets added to it?
+
+## Note
+
+- This exercise only accepts positive integers. If there is a negative input, then it should return an error.
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