diff --git a/datetimes.Rmd b/datetimes.Rmd
index ce6f5c6..5dc915c 100644
--- a/datetimes.Rmd
+++ b/datetimes.Rmd
@@ -539,17 +539,15 @@ knitr::include_graphics("diagrams/datetimes-arithmetic.png")
 
 ### Exercises
 
-1.  Why is there `months()` but no `dmonths()`?
-
-2.  Explain `days(overnight * 1)` to someone who has just started learning R.
+1.  Explain `days(overnight * 1)` to someone who has just started learning R.
     How does it work?
 
-3.  Create a vector of dates giving the first day of every month in 2015.
+2.  Create a vector of dates giving the first day of every month in 2015.
     Create a vector of dates giving the first day of every month in the *current* year.
 
-4.  Write a function that given your birthday (as a date), returns how old you are in years.
+3.  Write a function that given your birthday (as a date), returns how old you are in years.
 
-5.  Why can't `(today() %--% (today() + years(1))) / months(1)` work?
+4.  Why can't `(today() %--% (today() + years(1))) / months(1)` work?
 
 ## Time zones