diff --git a/cw/cw.tex b/cw/cw.tex
index b4746a5..c189a4e 100644
--- a/cw/cw.tex
+++ b/cw/cw.tex
@@ -152,7 +152,7 @@
 		m= (30544, 6633)\times\begin{pmatrix}
 			1975 & 438\\
 			7548 & 1627\\
-		\end{pmatrix}^-1}\iff
+		\end{pmatrix}^{-1}\iff
 		m=(4,3)
 	$$