Vim can use maths to edit text

In technical writing, especially writing computer code, numbers are common. Sometimes you need to change these numbers using maths, e.g. increasing by + 1 the value representing column names in a for loop to operate on a matrix.

Vim allows editing numbers in this way, without ever dipping into insert mode: typing any number followed by <C-a> and <C-x> (think of “add” and “remove - x”) will result in the next instance of a number being increased or decreased by the specified amount.

‘http://vim.wikia.com/wiki/Recovering_file_’

triggers autocompletion of filenames relative to the current working directory. This is explained in a popular [stack overflow exchange](http://stackoverflow.com/questions/1919492/when-in-vim-insert-mode-is-there-a-way-to-add-filepath-autocompletion) deletes the current word in insert mode gq is a very powerful command, automatically breaking a long line (up to wherever you specify (e.g. "gqg" will break up all long lines until the end of the document).