diff --git a/src/content/1.6/Simple Algebraic Data Types.tex b/src/content/1.6/Simple Algebraic Data Types.tex
index d907cc6..b218191 100644
--- a/src/content/1.6/Simple Algebraic Data Types.tex	
+++ b/src/content/1.6/Simple Algebraic Data Types.tex	
@@ -470,7 +470,7 @@ other, but if you think about it, they must be! They are just trivially
 re-packing the contents of the two data structures. It's the same data,
 only different format.
 
-Mathematicians have a name for such two intertwined monoids: it's called
+Mathematicians have a name for two such intertwined monoids: it's called
 a \newterm{semiring}. It's not a full \newterm{ring}, because we can't define
 subtraction of types. That's why a semiring is sometimes called a
 \newterm{rig}, which is a pun on ``ring without an \emph{n}'' (negative).