diff --git a/CPP17.md b/CPP17.md
index 8909fec..adbc43a 100644
--- a/CPP17.md
+++ b/CPP17.md
@@ -64,7 +64,7 @@ auto seq2 = my_integer_sequence<0, 1, 2>();
 ### Folding expressions
 A fold expression performs a fold of a template parameter pack over a binary operator.
 * An expression of the form `(... op e)` or `(e op ...)`, where `op` is a fold-operator and `e` is an unexpanded parameter pack, are called _unary folds_.
-* An expression of the form `(e1 op ... op e2)`, where `op` are fold-operators, is called a _binary fold_. Either `e1` or `e2` are unexpanded parameter packs, but not both.
+* An expression of the form `(e1 op ... op e2)`, where `op` are fold-operators, is called a _binary fold_. Either `e1` or `e2` is an unexpanded parameter pack, but not both.
 ```c++
 template<typename... Args>
 bool logicalAnd(Args... args) {
diff --git a/README.md b/README.md
index 8700a65..4407e9a 100644
--- a/README.md
+++ b/README.md
@@ -125,7 +125,7 @@ auto seq2 = my_integer_sequence<0, 1, 2>();
 ### Folding expressions
 A fold expression performs a fold of a template parameter pack over a binary operator.
 * An expression of the form `(... op e)` or `(e op ...)`, where `op` is a fold-operator and `e` is an unexpanded parameter pack, are called _unary folds_.
-* An expression of the form `(e1 op ... op e2)`, where `op` are fold-operators, is called a _binary fold_. Either `e1` or `e2` are unexpanded parameter packs, but not both.
+* An expression of the form `(e1 op ... op e2)`, where `op` are fold-operators, is called a _binary fold_. Either `e1` or `e2` is an unexpanded parameter pack, but not both.
 ```c++
 template<typename... Args>
 bool logicalAnd(Args... args) {