Add "of" between numbers and rows

numbers.qmd

@@ -129,7 +129,7 @@ There are a couple of variants of `n()` and `count()` that you might find useful
 
 ### Exercises
 
-1.  How can you use `count()` to count the number rows with a missing value for a given variable?
+1.  How can you use `count()` to count the number of rows with a missing value for a given variable?
 2.  Expand the following calls to `count()` to instead use `group_by()`, `summarize()`, and `arrange()`:
     1.  `flights |> count(dest, sort = TRUE)`