diff --git a/cachematrix.R b/cachematrix.R
index a50be65aa44..3ff7a3c2e15 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -4,6 +4,22 @@
 ## Write a short comment describing this function
 
 makeCacheMatrix <- function(x = matrix()) {
+    # returns a list of functions for:
+    # - setting the matrix x
+    # - getting the matrix x
+    # - setting the inverse of the matrix x (s)
+    # - getting the inverse of the matrix x
+    s <- NULL
+    set <- function(y) {
+            x <<- y
+            s <<- NULL
+    }
+    get <- function() x
+    setinverse <- function(inverse) s <<- inverse
+    getinverse <- function() s
+    list(set = set, get = get,
+            setinverse = setinverse,
+            getinverse = getinverse)
 
 }
 
@@ -11,5 +27,16 @@ makeCacheMatrix <- function(x = matrix()) {
 ## Write a short comment describing this function
 
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+    ## Return a matrix that is the inverse of 'x'
+    s <- x$getinverse()
+    # return cached inverse if it exists
+    if(!is.null(s)){
+        message("getting cached inverse")
+        return(s)
+    }
+    # otherwise call solve to get the inverse and set it
+    data <- x$get()
+    s <- solve(data, ...)
+    x$setinverse(s)
+    s
 }