Here is a list of common expressions about numbers.

First footer

First footer is the first person to enter a house on the New Year day.

First string player

The most skilled player

One-horse town

A small, old-fashioned and boring town

One-liner

A short joke or a funny remark

Look after number one

To look after oneself and not worry about others

Second banana

A person in a subservient position

Play second fiddle

To be of secondary importance

Second-string

A substitute player, used when somebody else is not available

Second wind

A new strength or energy to continue something that requires tremendous exertion

Two-time

To two-time is to be unfaithful to your spouse or lover.

Two-way street

A situation that requires the cooperation of two people

Third degree

A euphemism for inflicting physical and mental pain to extract confessions

Third world

This label is used to refer to the poor, undeveloped countries of Africa and Asia

Fourth Estate

A label used to refer to the press. The other three are the Clergy, the Lords and the Commons

Four-letter word

A rude and offensive word

Fifth column

A group of people who work secretly for the enemy

Fifth wheel

This label is used to refer to a person who is unnecessary or unwelcome.

Sixth sense

Used to refer to your intuition

At sixes and sevens

In utter confusion or disorder

In seventh heaven

When you are in seventh heaven, you are supremely happy.

On cloud nine

When you are on cloud nine, you are extremely happy.

Nine day’s wonder

This label is used to refer to something that loses its appeal after a few days.