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-x> (think of “add” and “remove - x”)
will result in the next instance of a number being increased or
decreased by the specified amount.