Update README's

exercises/difference-of-squares/README.md

@@ -12,6 +12,10 @@ Hence the difference between the square of the sum of the first
 ten natural numbers and the sum of the squares of the first ten
 natural numbers is 3025 - 385 = 2640.
 
+You are not expected to discover an efficient solution to this yourself from
+first principles; research is allowed, indeed, encouraged. Finding the best
+algorithm for the problem is a key skill in software engineering.
+
 ## Hints
 This exercise requires you to process a collection of data. You can simplify your code by using LINQ (Language Integrated Query).
 For more information, see [this page]

exercises/dnd-character/README.md

@@ -1,4 +1,4 @@
-# Dnd Character
+# D&D Character
 
 For a game of [Dungeons & Dragons][DND], each player starts by generating a
 character they can play with. This character has, among other things, six

exercises/grains/README.md

@@ -6,14 +6,14 @@ on each square doubles.
 There once was a wise servant who saved the life of a prince. The king
 promised to pay whatever the servant could dream up. Knowing that the
 king loved chess, the servant told the king he would like to have grains
-of wheat. One grain on the first square of a chess board. Two grains on
-the next. Four on the third, and so on.
+of wheat. One grain on the first square of a chess board, with the number
+of grains doubling on each successive square.
 
-There are 64 squares on a chessboard.
+There are 64 squares on a chessboard (where square 1 has one grain, square 2 has two grains, and so on).
 
 Write code that shows:
-- how many grains were on each square, and
-- the total number of grains
+- how many grains were on a given square, and
+- the total number of grains on the chessboard
 
 ## For bonus points
 

exercises/high-scores/README.md

@@ -2,7 +2,7 @@
 
 Manage a game player's High Score list.
 
-Your task is to build a high-score component of the classic Frogger game, one of the highest selling and addictive games of all time, and a classic of the arcade era. Your task is to write methods that return the highest score from the list, the last added score, the three highest scores, and a report on the difference between the last and the highest scores.
+Your task is to build a high-score component of the classic Frogger game, one of the highest selling and addictive games of all time, and a classic of the arcade era. Your task is to write methods that return the highest score from the list, the last added score and the three highest scores.
 
 ## Running the tests
 

exercises/leap/README.md

@@ -13,9 +13,6 @@ on every year that is evenly divisible by 4
 For example, 1997 is not a leap year, but 1996 is.  1900 is not a leap
 year, but 2000 is.
 
-If your language provides a method in the standard library that does
-this look-up, pretend it doesn't exist and implement it yourself.
-
 ## Notes
 
 Though our exercise adopts some very simple rules, there is more to

exercises/saddle-points/README.md

@@ -8,7 +8,7 @@ So say you have a matrix like so:
     1  2  3
   |---------
 1 | 9  8  7
-2 | 5  3  2     <--- addle point at column 1, row 2, with value 5
+2 | 5  3  2     <--- saddle point at column 1, row 2, with value 5
 3 | 6  6  7
 ```
 

exercises/sgf-parsing/README.md

@@ -18,9 +18,10 @@ An SGF file may look like this:
 
 This is a tree with three nodes:
 
-- The top level node has two properties: FF\[4\] (key = "FF", value =
-  "4") and C\[root\](key = "C", value = "root"). (FF indicates the
-  version of SGF and C is a comment.)
+- The top level node has three properties: FF\[4\] (key = "FF", value
+  = "4"), C\[root\](key = "C", value = "root") and SZ\[19\] (key =
+  "SZ", value = "19"). (FF indicates the version of SGF, C is a
+  comment and SZ is the size of the board.)
   - The top level node has a single child which has a single property:
     B\[aa\].  (Black plays on the point encoded as "aa", which is the
     1-1 point (which is a stupid place to play)).