diff --git a/slides/chapter-09.de.md b/slides/chapter-09.de.md
index 6a14fc5..eab3f87 100644
--- a/slides/chapter-09.de.md
+++ b/slides/chapter-09.de.md
@@ -50,7 +50,7 @@ Einige Beispiele
$e^{\pi}$ |
- | `\sum_{i=1}\^{n}x^2` |
+ `\sum_{i=1}^{n}x^2` |
$\sum_{i=1}^{n} x^2$ |
diff --git a/slides/chapter-09.en.md b/slides/chapter-09.en.md
index 51479c0..2d571cd 100644
--- a/slides/chapter-09.en.md
+++ b/slides/chapter-09.en.md
@@ -52,7 +52,7 @@ Examples
| $e^{\pi}$ |
- | `\sum_{i=1}\^{n}x^2` |
+ `\sum_{i=1}^{n}x^2` |
$\sum_{i=1}^{n} x^2$ |