Some typographic fixes

README.md

@@ -15,29 +15,29 @@
 * [Jest Expect](https://facebook.github.io/jest/docs/en/expect.html#content)
 
 ## Configuration 
-Configure the root of your repository with the following files and directories. Thoughfully name and organize any aditional configuration or module files.
+Configure the root of your repository with the following files and directories. Thoughtfully name and organize any additional configuration or module files.
 * **README.md** - contains documentation
 * **.gitignore** - contains a [robust](http://gitignore.io) `.gitignore` file 
-* **.eslintrc** - contains the course linter configuratoin
+* **.eslintrc** - contains the course linter configuration
 * **.eslintignore** - contains the course linter ignore configuration
 * **lib/** - contains module definitions
 * **__test__/** - contains unit tests
 
 ## Feature Tasks
 #### Greet Module
 Create a NodeJS module in the lib/ directory named `greet.js` that exports a single function. 
-* The `greet` function should have a single parameter (arity of one) that should expect a string as it's input
+* The `greet` function should have a single parameter (arity of one) that should expect a string as its input
 * The `greet` function should return the input name, concatenated with "hello ": eg. ("hello susan")
 * The `greet` function should return `null` if the input is not a string
 
 #### Arithmetic Module
-Create a NodeJS module in the lib/ directory named `arithmetic.js` that exports an object. This module should have `add` and `sub` methods that implament addition and subtraction.  
-* The `add` method should have an arity of two (define two paramiters)
+Create a NodeJS module in the lib/ directory named `arithmetic.js` that exports an object. This module should have `add` and `sub` methods that implement addition and subtraction.  
+* The `add` method should have an arity of two (define two parameters)
   * If either parameter is a non-number the function should return null
   * Else return the sum of the 2 numbers
-* The `sub` method should have an arity of two (define two paramiters)
+* The `sub` method should have an arity of two (define two parameters)
   * If either parameter is a non-number the function should return null
-  * Else return the second paramiter subtracted from the first paramiter
+  * Else return the second parameter subtracted from the first parameter
 
 ## Testing  
 #### Greet Module Tests
@@ -46,8 +46,8 @@ Create a NodeJS module in the lib/ directory named `arithmetic.js` that exports
   * This should happen when invoked with `'world'` as the first argument
 
 #### Arithmetic Module Tests
-* Test each method for proper use (invoded with number arguments)
-* Test each method for inproper use (invoded with one or more non-numner arguments)
+* Test each method for proper use (invoked with number arguments)
+* Test each method for improper use (invoked with one or more non-number arguments)
 
 ## Documentation  
-In your README.md describe the exported values of each module defined in your lib/ directory. Every function description should include it's airty (expected number of paramiters), the expected data for each paramiter (data-type and limitations), and it's behavior (for both valid and invalued use). Feel free to write any additional information in your README.md.
+In your README.md describe the exported values of each module defined in your lib/ directory. Every function description should include its arity (expected number of arguments), the expected data for each argument (data-type and limitations), and its behavior (for both valid and invalid use). Feel free to write any additional information in your README.md.