Edited ch12_mining.adoc with Atlas code editor

ch12_mining.adoc

@@ -779,10 +779,10 @@ finding a hash that is less than the target becomes more and more
 difficult.
 
 ++++
-<p class="fix_tracking">
+<p class="fix_tracking2">
 To give a simple analogy, imagine a game where players throw a pair of
 dice repeatedly, trying to throw less than a specified target. In the
-first round, the target is 12. Unless you throw double-six, you win. In
+first round, the target is 12. Unless you throw double-6, you win. In
 the next round the target is 11. Players must throw 10 or less to win,
 again an easy task. Let's say a few rounds later the target is down to
 5. Now, more than half the dice throws will exceed the target and