diff --git a/transform.Rmd b/transform.Rmd
index 03a0a45..3c6564d 100644
--- a/transform.Rmd
+++ b/transform.Rmd
@@ -877,7 +877,7 @@ Functions that work most naturally in grouped mutates and filters are known as
 1.  What time of day should you fly if you want to avoid delays as much
     as possible?
     
-1.  For each destination, compute the total minutes of delay. For each, 
+1.  For each destination, compute the total minutes of delay. For each 
     flight, compute the proportion of the total delay for its destination.
     
 1.  Delays are typically temporally correlated: even once the problem that
diff --git a/visualize.Rmd b/visualize.Rmd
index 717a007..7e6ef96 100644
--- a/visualize.Rmd
+++ b/visualize.Rmd
@@ -294,7 +294,7 @@ If you prefer to not facet in the rows or columns dimension, use a `.` instead o
     
 1.  Read `?facet_wrap`. What does `nrow` do? What does `ncol` do? What other
     options control the layout of the individual panels? Why doesn't
-    `facet_grid()` have `nrow` and `ncol` argument?
+    `facet_grid()` have `nrow` and `ncol` arguments?
 
 1.  When using `facet_grid()` you should usually put the variable with more
     unique levels in the columns. Why?