# Work with numbers in Vim

- The expression register
`=`

`<C-a>`

`<C-x>`

in normal mode

## Expression register `=`

The expression register can evaluate a piece of Vim script code
Access it with `<C-r>=`

in insert mode.
It can evaluate arithmetic expressions e.g:

```
body { font-size: 16px; }
h1 { font-size: 1.25rem; //20px}
```

The `rem`

value could be calculated directly in insert mode
with following `<C-r>=16.0/20.0<CR>`

combination.

When on the right position type CTRL + r followed with = and
after that the arithmetic expression followed with `_ENTER_`

the result
will be inserted automatically.

## Normal mode direct addition and subtraction with counters

Using `<C-a>`

will jump to first found number on line.
But if added some whole number it will add it to the number directly

```
.pannel{padding 10px;} // 29<C-a> will change the line to
.pannel{padding 39px;}
```

Alternatively `<C-x>`

will subtract from number so

```
p { margin-top: 0px; } // 20<C-x> will change it to
p { margin-top: -20px;}
```