diff --git a/tidy.Rmd b/tidy.Rmd
index 7c469e9..0a69c48 100644
--- a/tidy.Rmd
+++ b/tidy.Rmd
@@ -49,7 +49,7 @@ Figure \@ref(fig:tidy-structure) shows the rules visually.
 knitr::include_graphics("images/tidy-1.png")
 ```
 
-These three rules are interrelated because it's impossible to only satisfy two of the three. That interrelationship leads to even simpler set of practical instructions:
+These three rules are interrelated because it's impossible to only satisfy two of the three. That interrelationship leads to an even simpler set of practical instructions:
 
 1.  Put each dataset in a tibble.
 1.  Put each variable in a column.