diff --git a/algebra.tex b/algebra.tex
index b7d3d882e..68b16d46b 100644
--- a/algebra.tex
+++ b/algebra.tex
@@ -36594,7 +36594,7 @@ \section{Formally \'etale maps}
 
 \noindent
 Clearly a ring map is formally \'etale if and only if
-it is booth formally smooth and formally unramified.
+it is both formally smooth and formally unramified.
 
 \begin{lemma}
 \label{lemma-formally-etale-etale}