More simple typos

ch09.md

@@ -387,7 +387,7 @@ In the next chapter, we'll see how applicative functors fit into the container w
 ## Exercises
 
 
-Condering a User object as follow:
+Considering a User object as follow:
 
 ```js  
 const user = {  

ch10.md

@@ -333,7 +333,7 @@ We're almost finished with container apis. We've learned how to `map`, `chain`,
 ## Exercises
 
 {% exercise %}  
-Write a function that add's two possibly null numbers together using `Maybe` and `ap`.  
+Write a function that adds two possibly null numbers together using `Maybe` and `ap`.  
 
 {% initial src="./exercises/ch10/exercise_a.js#L3;" %}  
 ```js  

ch12.md

@@ -250,7 +250,7 @@ const validate = player => (player.name ? Either.of(player) : left('must have na
 
 {% exercise %}  
 Using traversable, and the `validate` function, update `startGame` (and its signature)
-to only start the game is all players are valid
+to only start the game if all players are valid
 
 
 {% initial src="./exercises/ch12/exercise_b.js#L7;" %}  

exercises/ch09/exercise_a.js

@@ -1,4 +1,4 @@
-// Condering a User object as follow:
+// Considering a User object as follow:
 //
 //   const user = {
 //     id: 1,

exercises/ch10/exercise_a.js

@@ -1,4 +1,4 @@
-// Write a function that add's two possibly null numbers together using `Maybe` and `ap`.
+// Write a function that adds two possibly null numbers together using `Maybe` and `ap`.
 
 // safeAdd :: Maybe Number -> Maybe Number -> Maybe Number
 const safeAdd = undefined;

exercises/ch12/exercise_b.js

@@ -1,5 +1,5 @@
 // Using traversable, and the `validate` function, update `startGame` (and its signature)
-// to only start the game is all players are valid
+// to only start the game if all players are valid
 //
 //   // validate :: Player -> Either String Player
 //   validate = player => (player.name ? Either.of(player) : left('must have name'));