Vim is a great text editor and I'm constantly surprised (and amazed) by the sort of things I discover you can do with it.
The latest surprise was :
if you place your cursor on a number and press Ctrl-a, the number is incremented by one. Ctrl-x on a number will decrement it by one. Further, modify the command with a count to increment or decrement by count i.e. 6 Ctrl-x decrements 6 from the number under the cursor.
Vim is full of odd little features like this.