A ruler which has inches marked, typically has fractions of an inch marked.

The image below shows ruler markings for one eighth of an inch, one fourth of an inch, and one half of an inch.

In the image below, the first pencil is

$2\frac{1}{4}$ inches long.

The second pencil is

$2\frac{1}{2}$ inches long.

The third pencil is

$3\frac{1}{8}$ inches long.