diff --git a/manuscript/regex.Rmd b/manuscript/regex.Rmd
index 33b0611..9babb04 100644
--- a/manuscript/regex.Rmd
+++ b/manuscript/regex.Rmd
@@ -221,7 +221,7 @@ Notice that the `sub()` function found the first match (at the beginning of the
 gsub("<dd>[F|f]ound on |</dd>", "", x)
 ```
 
-The `sub() and `gsub()` functions can take vector arguments so we don't have to process each string one by one.
+The `sub()` and `gsub()` functions can take vector arguments so we don't have to process each string one by one.
 
 ```{r}
 r <- regexpr("<dd>[F|f]ound(.*?)</dd>", homicides[1:5])
diff --git a/manuscript/regex.md b/manuscript/regex.md
index 9758c19..0008e7d 100644
--- a/manuscript/regex.md
+++ b/manuscript/regex.md
@@ -309,7 +309,7 @@ Notice that the `sub()` function found the first match (at the beginning of the
 [1] "January 1, 2007"
 ~~~~~~~~
 
-The `sub() and `gsub()` functions can take vector arguments so we don't have to process each string one by one.
+The `sub()` and `gsub()` functions can take vector arguments so we don't have to process each string one by one.
 
 
 {line-numbers=off}