Minor changes to 1987

Typo fix in 1987/biggar/README.md.

Add another try in 1987/wall/README.md with a question to ponder.

1987/biggar/README.md

@@ -35,7 +35,7 @@ One vendor's lint got hung in an infinite loop over this entry!
 > FYI:  We will let Mark get away with this truly sick entry this time, but 
 > for the future on we have placed a limit on the size of a compile line.
 
-NOTE: originally there we made a comment in [Larry Wall's
+NOTE: originally we made a comment in [Larry Wall's
 entry](../wall/README.md) regarding Mark's contribution but it seems to have
 been lost in time. If anyone knows about its whereabouts we'd appreciate letting
 us know. Thanks!

1987/wall/README.md

@@ -28,6 +28,9 @@ and input the following:
 	c^2
 	m*m
 
+	# can you figure out what this does?
+	500
+
 ### Also try:
 
 	./wall | bc