Fixed some minor typos.

README.md

@@ -1,14 +1,14 @@
 ### Introduction
 
 This second programming assignment will require you to write an R
-function is able to cache potentially time-consuming computations. For
+function that is able to cache potentially time-consuming computations. For
 example, taking the mean of a numeric vector is typically a fast
 operation. However, for a very long vector, it may take too long to
 compute the mean, especially if it has to be computed repeatedly (e.g.
 in a loop). If the contents of a vector are not changing, it may make
 sense to cache the value of the mean so that when we need it again, it
 can be looked up in the cache rather than recomputed. In this
-Programming Assignment will take advantage of the scoping rules of the R
+Programming Assignment you will take advantage of the scoping rules of the R
 language and how they can be manipulated to preserve state inside of an
 R object.
 
@@ -17,7 +17,7 @@ R object.
 In this example we introduce the `<<-` operator which can be used to
 assign a value to an object in an environment that is different from the
 current environment. Below are two functions that are used to create a
-special object that stores a numeric vector and cache's its mean.
+special object that stores a numeric vector and caches its mean.
 
 The first function, `makeVector` creates a special "vector", which is
 really a list containing a function to
@@ -64,8 +64,8 @@ function.
 
 ### Assignment: Caching the Inverse of a Matrix
 
-Matrix inversion is usually a costly computation and their may be some
-benefit to caching the inverse of a matrix rather than compute it
+Matrix inversion is usually a costly computation and there may be some
+benefit to caching the inverse of a matrix rather than computing it
 repeatedly (there are also alternatives to matrix inversion that we will
 not discuss here). Your assignment is to write a pair of functions that
 cache the inverse of a matrix.