diff --git a/cachematrix.R b/cachematrix.R
index a50be65aa44..9ed2eac198c 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -1,15 +1,43 @@
-## Put comments here that give an overall description of what your
-## functions do
-
-## Write a short comment describing this function
+##
+## repo: may-data-scientist-toolbox/ProgrammingAssignment2
+## I have two functions, makeCacheMatrix and cacheSolve, to get an
+## invertible matrix, calculate its inverse and cache the inverse
+## calculation.
+## 
+## 
+## makeCacheMatrix --- This function sets and gets the matrix,
+##                    and its inverse.
 
 makeCacheMatrix <- function(x = matrix()) {
-
+  inv <- NULL
+  set <- function(y) {
+    x <<- y
+    inv <<- NULL
+  }
+  get <- function() x
+  setinverse <- function(solve) inv <<- solve
+  getinverse <- function() inv
+  list(set = set, get = get,
+       setinverse = setinverse,
+       getinverse = getinverse)
 }
 
 
-## Write a short comment describing this function
-
+## 
+##
+## cacheSolve --- This function gets the matrix from above and 
+## gets the cached (already calculated) inverse of this matrix, 
+## skipping the calculation of inverse again.
+## 
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+  ## Return a matrix that is the inverse of 'x'
+  inv <- x$getinverse()
+  if(!is.null(inv)) {
+    message("getting cached inverse")
+    return(inv)
+  }
+  data <- x$get()
+  inv <- solve(data, ...)
+  x$setinverse(inv)
+  inv
 }